Avalanche Discussion

1. The bulletin is an outstanding, high-quality resource that is simply not applicable at the slope scale. It is dangerous to use a synoptic scale or mesoscale forecast product as the sole source of information for go/no go decisions. From trip reports, it seems most TAY members pay attention and evaluate instability in the field - regardless of the bulletin. This is definitely the right course of action. Relying on the bulletin is foolish.

1. Your post disagrees with my thoughts on using the bulletin at the slope scale. I'll explain my reasoning.

The bulletin is a great tool for choosing which mountains to go ski ( or whether to go out at all ) but the scale of the information
( synoptic scale and sometimes mesoscale ) doesn't match the scale of an individual slope ( the slope scale ).

Nobody that I know is relying on the bulletin as the sole source of go/no go decisions. What I was saying is that this thread has over-emphasized slope scale, etc. arguments at the disadvantage of losing track of the value of avalanche bulletins as a planning tool. That is one of their chief values. Along with telemetry and trip reports the bulletins do provide the best source for trip planning - call this macro routefinding decisions - planning where one will ski. I obviously then went on to say that observations, visual and other, allow one to modify one's initial plan at a meso scale - different slope or specific route. Extremely small scale - micro scale modifications of route - are then made based on visual and other observational cues.

The value of the bulletin is enormous in choosing an initial plan and has slope specific value with respect to aspect and for choosing tests and locations for such tests.

2. Avalanche forecasting is a Bayesian activity. This requires the prior ( data about the history of the terrain, weather, and snowpack ) and the likelihood ( data about the current terrain, weather, and snowpack. ) Finally, the posterior ( the prediction ) is assembled.
One important characteristic of Bayesian revision is that a single piece of data ( cracking in the snowcover ) has the power to completely revise the entire forecast.

I don't disagree. Any observation allows one a decision point for modifying one's plan or route.

According to The Avalanche Handbook, you can't form an accurate prediction without the prior and the likelihood. The bulletin does not include information on instability for specific slopes ( the likelihood ). Furthermore, The Avalanche Handbook specifically states that over-reliance on the bulletin is probably the source of many backcountry accidents.

I think you are over reaching here. The bulletin speaks to aspect, often specific regions, and specific snowpack problems such as surface hoar or a faceted suncrust in the worst case scenario. Likewise being aware of a glaze or freezing drizzle crust apparently near the volcanoes (at least) is very pertinent - although not slope specific.

3. Your post doesn't actually address the key problem with observations.

Observations and data sampling, especially snowpits, form much of the basis for perception of instability. Problems arise when these observations foster "false stable perception". It's like the proverb: "absence of evidence is not evidence of absence".

This is especially important during conditional instability - which is the prevailing state of the winter snowpack. Perception is always poorer during conditional instability than absolute instability and low instability. Data sampling can be a helpful, or harmful, part of the search for instability.

Nor was I trying to address the issue of stability tests in a general sense since making observations is a no brainer.

Anyway, poor visibility and the well-known difficulties of extrapolating slopeside instability tests across a wider area, aren't nearly as important as how the results of observations alter the recreationist's perception of instability.

Visual observations of wind effects are very critical in forming an initial expectation for new snow instabilities on certain slopes and can be very valuable in wet snow instabilities.

The correct procedure during poor visibility, or any other high uncertainty situation, is to implement a very wide margin of safety.

And not to travel above treeline in periods of higher hazard with poor visibility.

4. Quote: "Persistent weak layers are easier to trigger when deeply buried than are most storm snow layers and triggering a deep weak layer obviously opens the door for the worst of potential consequences."

I profoundly disagree with your statement.

You misread it. Deeply buried weak layers are easier to trigger than are storm snow weak layers of the same depth because persistently weak layers have very low bond densities and are with a few exceptions weaker than are storm snow layers by the time such layers are deeply buried. Although one could argue that storm snow layers could also be very weak, by the time they are buried more than a couple of feet storm snow interfaces tend to have gained some strength.

Skier triggering of instabilities below 1 meter is rare.

If you want to talk about deeply buried weaknesses, you have to discuss the problem of perception. The persistent forms, when deeply buried, present a very serious perception problem, regardless of the energy required to release the slope.

Deeply buried persistent forms are not easy to trigger when skiing. Shallowly buried persistent forms can be skier-triggered and the fracture can propagate to areas where the snowpack is very deep.

I'm surprised you would even say that "deeply buried weaknesses are easier to trigger" because it's not true.

Disagree. Rare but less so with persistent weaknesses. I've triggered 3' and 4' slabs myself. Also, deeply buried weaknesses are often triggered from areas where overlying burden is shallower (which can be difficult to know - as is true apparently in the northern Rockies right now due to wind effects) or can be triggered when shallower weaknesses step down. In any case more deeply buried persistent weaknesses when they fail- as at Washington Pass and in Canada according to reports within the last couple of weeks - are likely to be catastrophic. Therefore, the fact that they are a meter or more buried is more than offset by the potential consequences when triggered.

Soft slab avalanches that run in storm snow are responsible for many fatalities.

True, but easier to manage.

Once again, winter 2003 is discussed. Those famous accidents occurred because a large number of people were in harm's way. I'm not sure I see the parallel between the snowpack that is hundreds of miles away ( and in a different snow climate ) and the snowpack that is "right here, right now"?

Bad weak layers are often regional. The Xmas weak layer this year was present from Oregon to Washington, from BC to Alberta to Montana and likely farther SE into the US Rockies. The high freezing levels and wet snow/ rain that mitigated that problem did so from Oregon and southern Washington initially and then to a lesser degree into Northern Washington and coastal BC. The extremely high freezing levels of late affected most of Western North America resulting initially in greater instabilities and thenceforth in slow strength gain of snowpack upper layers.

I've heard forecasters in Revelstoke compare the current snowpack in their area to the winter of 2003 but I haven't heard any forecasters in Washington compare the snowpack here to the snowpack in the southern interior of British Columbia. I'm not sure how/why the avalanche bulletin up at Rogers Pass ( I take it that's the Glacier Park to which you refer ) has any relevance to conditions here in the Cascades?

That they didn't mention it doesn't mean it wasn't the case. I am sure that digging a pit to the base of the snowpack at Washington Pass would yield the same weak layer as at Rogers Pass, the only difference being some consolidation at Washington Pass due to overburden pressure from very heavy snows the first week of January.

But all this aside, it is true that deep instabilities have a well-deserved reputation for producing very dangerous avalanches. However, I'd hate to have someone read this thread and think that storm snow instabilities are harder to trigger than deep instabilities.

Yet buried at the same depth that is the case. Nothing can be weaker than buried surface hoar or an advanced layer of depth hoar so it only makes sense that the weaker the layer the easier it is to trigger. Note for evidence that avalanches routinely slide on lower slope angles (poorer bonding) with persistent weaknesses.

6. Quote: "We should really be preparing ourselves for the likely eventuality of a bad persistent weak layer once there is sufficient load and cohesion overlying the existing surface structure."

What does this mean? Did you mean to say "We should prepare ourselves for another avalanche cycle once there is a cohesive slab overlaying a persistent weak layer."?

Otherwise, can you clarify your statement?

Load and cohesion are good for stability in the long term.

It will take an initial thin snowfall, subsequent faceting and loading, especially as cohesion is gained to lead to a highly unstable snowpack. By long term I assume you are talking about over time, whereas instabilities will arise with a gain in cohesiveness sufficient for propagation.

7. Ice glaze.

Sure an ice glaze exists in places. However the temperature of the snow that falls onto the ice glaze, and the temperature difference between the ice glaze and the new snow crystals, is what determines how the new snow bonds to the ice glaze.

Does it seem reasonable to expect a nice soft slab cycle to run on this glaze? Sure. In some places. Does it seem reasonable to expect a nice soft slab cycle to run in places where this glaze isn't found? Sure. In some places.

Is this ice glaze the layer to watch? Possibly.

I'll be worried about an ice glaze so slick that a fall on a 20 degree angle probably couldn't be stopped. I'll also be worried about what looks like it will be a very poor bond at most elevations and on most aspects to a very different old snow surface than the soon to come new snowfall.

But with the general powder hound culture in these parts, I'd probably be more concerned about instabilities in new snow ( soft slab avalanches ).

With sufficent snowfall and wind, but the weakness that will be of most concern for the longest period of time will be the bond to the existing surface and a high likelihood of near surface faceting of the first snowfall in the next cycle. Concern for storm snow instabilities will (with sufficient load and cohesiveness) will soon be outweighed by concern for dangerous deeper slabs.

8. Quote: "New information on the ECT may provide some greater confidence but the test itself is very new."

Did you mean propagation saw test? Because as far as I'm aware, the ECT has been validated. Doesn't the ECT result in fewer "false stable" results ... and more "false unstable" results? The ECT is specifically designed to balance fracture propensity with propagation propensity - very helpful for instabilities in new snow.

Validated by one or two sets of observations. It's still new.

9. Quote: "With persistent weakness I would personally rely to a greater extent on the avalanche forecast (which is based in part on multiple observations like the professional INFO-EX in Canada)."

My thoughts are that persistent weaknesses call for conservative terrain choices. I bet most avalanche professionals would agree. Relying on the bulletin is not the same as making conservative terrain choices.

It is ultimately all about terrain. The bulletin, especially when it calls attention to very weak persistent layers tells me that my terrain choices have to be all the more conservative - that also means that I have question whether I should be trusting of my test results if they lead me to believe that a particular steep slope is skiable . I have to consider (as always) the consequences of triggering.

Thanks for the discourse Cookie Monster.

I'll try to keep this simple... I take into consideration every bit of information and don't consider any of it gospel... Since I'm probably going to ski something most of the time, I take responsibility for my decision making --and since I'm probably wrong about how stable things are anyway (don't know anybody that can out smart the snowpack), I try to play it conservative and think of what slope would have the lesser of evil consequences (including the route back out from the bottom...) if I was to screw up on my evaluation--and hope for the best (or not ski anything sometimes!!!).

A few weeks back I skied Tumalo Mountain down here in Central Oregon (alone...a rare thing even if one wanted to..). Did three laps on the back as it seemed stable. A friend of mine said "oh it's stable..I'll head up tomorrow" after giving him my details of my ski day. I told him not to take my word about stability as it was just my "take". Point here is that I would not want anybody to think something was stable just because I thought my day was a stable ski day. Things change of course and so we all have to make our own final "evaluation" and decision--not rely on somebody elses.

Years ago the phrase "all the experts are dead" (grim, sorry...) was sort of circulating (regarding avalanche science...) I guess meaning you can't outsmart the snowpack.... Rumour has we are suppose to get 6" of new by Sun!!!! Fingers crossed for freshies......

Maybe we can try this again. This thread, especially posts by prominent local experts, is going to influence perception of instability in the Cascade Mountains. Therefore, I really think we should get this right.

Rather than argue with a local expert, I've formulated some questions for Gary_Brill. The only reason I'm asking these questions is because Gary_Brill is a local expert who has made some pretty strong statements about what to expect in the Cascade snowpack for winter 2009. I think, as you are an expert and a local educator of some reknown, that I would personally find it very useful if you could provide some additional clarification.

1. Quote: "We should really be preparing ourselves for the likely eventuality of a bad persistent weak layer once there is sufficient load and cohesion overlying the existing surface structure."

---- If correct, this is an important prediction. Do you mind explaining your basis?
---- Do you have evidence? Snow profiles from a variety of areas. That sort of thing?

2. Quote: "In general the bond of eventual new snow is not likely to be very good even absent this ice glaze."

---- If correct, this is an important prediction. Do you mind explaining your basis?

3. Quote: "It's worth noting that CMH in Canada ruled out by fiat 2/3 of it's heli-skiing terrain in the winter of 2002-3; a winter dominated by unpredictable and multiple persistent weaknesses."

---- Does Canadian Mountain Holidays have any ski tenures in the Cascade Mountains or are all their ski tenures in the Columbia Mountains?

---- How is the decision making process at Canadian Mountain Holidays during the winter of 2003 relevant to snow conditions in the Cascade Mountains for winter 2009?

4. Quote: "Glacier National Park forecasters maintained a high rating for nearly a ten day period due to such weaknesses. Natural slides were still coming down and results from control work were definitive."

---- How are snow conditions and avalanche conditions at Rogers Pass, which is the interior mountains of British Columbia, relevant to snow conditions in the Cascade Mountains for winter 2009? Your previous answer "regional phenomenon" is fine but I'd like to see some evidence in support of this rather than speculation. Otherwise, it's just speculation.

5. Quote: "In snowpacks with sufficiently buried weak layers I think it wisest not to try to forecast stability on most slopes (perhaps with a few exceptions) but rather to turn one's attention to the consequences of triggering a slide."

---- On what are you basing this advice? I only ask because this statement is a rule of thumb. Have you considered that some people might take your advice and forgo instability tests on slopes? Is that your advice?

6. Quote: "This is especially so with snowpacks dominated by persistent weakness."

---- Where is the evidence that the Cascade snowpack for winter 2009 is dominated by persistent weaknesses? Do you mean now or in the future? If you mean the future, do you mind explaining the basis for this prediction?

7. Quote: "Deeply buried weak layers are easier to trigger than are storm snow weak layers of the same depth because persistently weak layers have very low bond densities and are with a few exceptions weaker than are storm snow layers by the time such layers are deeply buried."

---- Do you have evidence to support this statement? Do you think a quick review of avalanche accidents in Washington State from 1995-2008 supports this statement?

8. Quote: "The extremely high freezing levels of late affected most of Western North America resulting initially in greater instabilities and thenceforth in slow strength gain of snowpack upper layers."

---- Are you absolutely sure that high freezing levels result in slow strength gains in the upper layers of the snowpack? Does instability persist longer in colder temperatures or warmer temperatures?

9. Quote: "Note for evidence that avalanches routinely slide on lower slope angles (poorer bonding) with persistent weaknesses."

---- Are you sure that poor bonding is the reason? Is it possible that there are other reasons that might be more important? Is it possible that numerous factors, such as the strength of the weak layer itself and the stiffness of the slab at the interface might be more important?

10. Quote: "Concern for storm snow instabilities will (with sufficient load and cohesiveness) will soon be outweighed by concern for dangerous deeper slabs."

---- If correct, this is an important prediction. Do you mind explaining your basis?

11. Quote: "Validated by one or two sets of observations. It's still new."

----  Are you sure the ECT has only been validated by one or two sets of observations?

I'm not trying to be snarky. Gary_Brill has made some interesting predictions and statements. I'm curious.

Maybe we can try this again. This thread, especially posts by prominent local experts, is going to influence perception of instability in the Cascade Mountains. Therefore, I really think we should get this right.

Rather than argue with a local expert, I've formulated some questions for Gary_Brill. The only reason I'm asking these questions is because Gary_Brill is a local expert who has made some pretty strong statements about what to expect in the Cascade snowpack for winter 2009. I think, as you are an expert and a local educator of some reknown, that I would personally find it very useful if you could provide some additional clarification.

1. Quote: "We should really be preparing ourselves for the likely eventuality of a bad persistent weak layer once there is sufficient load and cohesion overlying the existing surface structure."

---- If correct, this is an important prediction. Do you mind explaining your basis?
---- Do you have evidence? Snow profiles from a variety of areas. That sort of thing?

2. Quote: "In general the bond of eventual new snow is not likely to be very good even absent this ice glaze."

---- If correct, this is an important prediction. Do you mind explaining your basis?

My evidence is based on observation and I am trying to weave in experience from previous snowpack and weather scenarios that I believe are about to play out once again. From the current avalanche forecast this morning:

"The main dangers from the current snowpack are not
avalanche related currently, but stem primarily from
potential damage due to loss of edge and a resulting long
slide on the crust or possible injury from unsuccessful
negotiation of the semi-breakable crust. However, the
currently stable snowpack structure is becoming well
primed for a significant increase whenever appreciable
future new snowfall arrives, as the bond of new snow to
either the crust or surface hoar should be quite weak."

There is more information based on what appears to be snowpack evaluation in the current forecast.

3. Quote: "It's worth noting that CMH in Canada ruled out by fiat 2/3 of it's heli-skiing terrain in the winter of 2002-3; a winter dominated by unpredictable and multiple persistent weaknesses."

---- Does Canadian Mountain Holidays have any ski tenures in the Cascade Mountains or are all their ski tenures in the Columbia Mountains?

---- How is the decision making process at Canadian Mountain Holidays during the winter of 2003 relevant to snow conditions in the Cascade Mountains for winter 2009?

The point I was trying to make is that at CMH where one can safely say that the level of skill and experience is unsurpassed, in the presence of a very bad snowpack, their experts chose to simply rule out many runs rather than to try to evaluate each on the basis of snowpack evaluative skills. In otherwords they did the very same thing that a backcountry skier might do in the planning phase of a trip after viewing a concerning avalanche forecast. The difference is that their decision was based on their own perception (from multiple observations) of a scary snowpack combined with confirmation from other operators and entities through INFO-EX which is more or less the professional version of the snowpack exchange and avalanche forecasts we as recreationalists get.

4. Quote: "Glacier National Park forecasters maintained a high rating for nearly a ten day period due to such weaknesses. Natural slides were still coming down and results from control work were definitive."

---- How are snow conditions and avalanche conditions at Rogers Pass, which is the interior mountains of British Columbia, relevant to snow conditions in the Cascade Mountains for winter 2009? Your previous answer "regional phenomenon" is fine but I'd like to see some evidence in support of this rather than speculation. Otherwise, it's just speculation.

As I mentioned previously extremely weak layers are often regional, but vary in degree. Roger's Pass was likely very similar to Washington Pass until the large snowfall at the latter the first week of January. Remeber that our own forecasts warned of very similar structure to Rogers Pass throughout the Cascades until the major avalanche cycles of earlier January. The avalanche cycle at Rogers Pass began and lasted later there because it didn't warm up as quickly.

5. Quote: "In snowpacks with sufficiently buried weak layers I think it wisest not to try to forecast stability on most slopes (perhaps with a few exceptions) but rather to turn one's attention to the consequences of triggering a slide."

---- On what are you basing this advice? I only ask because this statement is a rule of thumb. Have you considered that some people might take your advice and forgo instability tests on slopes? Is that your advice?

I'm not giving advice but merely stating what I do. A backcountry skier only need be wrong once. When the snowpack is very weak or unpredictable in strength and variability I would sooner look at the consequences and punt rather than try to prove my expertise and then bet my life on it. Conservative terrain choices are something you and I agree on Cookie Monster. I believe all the more so when known significant weak layers or weak bonds exist.

The way I look at backcountry skiing decisionmaking is sort of a decisionmaking tree that works like this for me:

What are the concerns in the snowpack? This is what Tremper refers to as the "AVALANCHE DRAGON". Recent snows absent weak layers? > Choose terrain away from the worst problems which are usually wind deposition until there has been a sufficient period of stabilization. Strong winds? > Stay below treeline when possible. Still snowing heavily or warming during snowfall? > Same choices but be wary of locations where natural slides may come into play. In all of these cases I rely on observations both visual and snowpack related and constantly engage myself in making observations of all types so that I am not surprised.

Still for aggressive terrain choices I think of it as though all the stars must be lined up. In otherwords the snowpack must be homogeneous and well consolidated by time and strength gain or the amount of snow that can slide has to be definitively limited by a very strong basal layer. I have more confidence in the latter of the two cases although it must remain cold in the latter case for reasonable stability. This usually means that there is a bombproof layer (like today's surface) with a limited amount of new snow reasonably bonded to it. This is something that is far more likely to happen in a maritime snowpack. Even in this situation there are slopes I usually avoid along with terrain traps.

Recent snows that have fallen onto one or more weak layers such as surface hoar, depth hoar, faceted crusts, near surface facets, or an ice layer? Watch out! Continue to make observations but don't rely on stability tests to justify marginal terrain choices. Rather choose less agressive terrain. Pay attention to the consequences of triggering, realize that remote triggering and extensive propagation are possible.

Spingtime diurnal instability? > Is the snowpack well set up (consolidated)? Aggressive skiing on sunny aspects while watching for increasing penetration or crustal weakening is likely OK. I am aware of the possibility of long falls on certain slopes. Is the crust marginal (barely supportive or not supportive on foot)? > This case is more problematic and either is representative of a poor freeze or of recent less than well consolidated snowfalls. One has to be quite careful and observant here as with minimal warming deeper slides may be possible.

6. Quote: "This is especially so with snowpacks dominated by persistent weakness."

---- Where is the evidence that the Cascade snowpack for winter 2009 is dominated by persistent weaknesses? Do you mean now or in the future? If you mean the future, do you mind explaining the basis for this prediction?

I wouldn't speculate on the whole winter although we recently went through such a period. But it does seem likely that for a period of time we will be dealing with a snowpack with a variety of poor bonding surfaces that may remain lasting concerns - i.e. will become persistent weaknesses - which really just means that new snow layers will not bond as well or as quickly to these surfaces.

7. Quote: "Deeply buried weak layers are easier to trigger than are storm snow weak layers of the same depth because persistently weak layers have very low bond densities and are with a few exceptions weaker than are storm snow layers by the time such layers are deeply buried."

---- Do you have evidence to support this statement? Do you think a quick review of avalanche accidents in Washington State from 1995-2008 supports this statement?

My own personal experience with close calls supports this statement. I can deal with storm snow weaknesses but find that when I have been surprised it is almost always with persistent weak layers. The best supporting evidence as I mentioned earlier is that avalanches typically release at lower angles (may release) on persistent weaknesses such as buried surface hoar, depth hoar, faceted crusts, near surface crusts, or ice layers. One fatal avalanche with depth hoar in the Rockies alledgedly released on a 15 degree slope. Surface hoar often releases down to angles in the low 20's but even lower angles are possible under rare conditions. I've personally released faceted crusts on low 30 degree angle slopes more than once. Corollary evidence comes from avalanche accidents where with these weak layers those involved have obviously had difficulty in evaluating slopes because the slopes that fail fall outside the range of the victims previous experience in terms of both angle and scale (propagation).

8. Quote: "The extremely high freezing levels of late affected most of Western North America resulting initially in greater instabilities and thenceforth in slow strength gain of snowpack upper layers."

---- Are you absolutely sure that high freezing levels result in slow strength gains in the upper layers of the snowpack? Does instability persist longer in colder temperatures or warmer temperatures?

I could try to answer the first part of that question but not the second because it is conditional. High freezing levels result in more rapid rates of settlement, but not necessarily on shady slopes with crust surfaces. Initially high settlement rates (flow rates) may redistribute stress in the snowpack in such a way that underlying weaknesses receive greater stress and could fail if sufficiently weak. In the long term the warming, if not at an increasing rate, causes the recently settled layers to densify and begin to bond more rapidly than they would otherwise. Confidence in a snowpack that has undergone warming is for me not a certain thing until subsequent cooling has taken place for a period of time. Crusts may inhibit settlement rates.

9. Quote: "Note for evidence that avalanches routinely slide on lower slope angles (poorer bonding) with persistent weaknesses."

---- Are you sure that poor bonding is the reason? Is it possible that there are other reasons that might be more important? Is it possible that numerous factors, such as the strength of the weak layer itself and the stiffness of the slab at the interface might be more important?

I gave my understanding on this earlier here, but:

There are always multiple factors. but probably it is worthwhile discussing static and dynamic friction. Weak layers are weaker and fail more easily because of low bond densities (with load) at lower angles. Once failed persistent weak layers are often made up of plate-like or sugary grains. Both of these structures are "slippery" - they slide easily. So anything on top of them also slides easily, at lower angles. The harder and smoother the bed surface - the lower it's capacity for dynamic friction, the easier is it for snow to slide.

10. Quote: "Concern for storm snow instabilities will (with sufficient load and cohesiveness) soon be outweighed by concern for dangerous deeper slabs."

---- If correct, this is an important prediction. Do you mind explaining your basis?

I believe the current snow surface will not allow for good bonding in many places and on a variety of aspects and will become persistent for some unknown period of time.

11. Quote: "Validated by one or two sets of observations. It's still new."

----  Are you sure the ECT has only been validated by one or two sets of observations?

I know of a couple of groups that have done validation tests for the ECT but only in the past 2-3 years.

I'm not trying to be snarky. Gary_Brill has made some interesting predictions and statements. I'm curious.

I hope this is helpful.

So, if I read through this whole thread, is that like taking Avy 1? Just kidding...

Gary, wow, thanks for sharing a lot of expertise here. I know you teach avy classes and are a reknowned expert and teacher. Have you written/published any books about evaluating snowpack or, I guess more specifically studying the snowpack in the cascades (maritime snowpack)? If so, should I just look on Amazon?

So, if I read through this whole thread, is that like taking Avy 1?   Just kidding...

Gary, wow, thanks for sharing a lot of expertise here.  I know you teach avy classes and are a reknowned expert and teacher.  Have you written/published any books about evaluating snowpack or, I guess more specifically studying the snowpack in the cascades (maritime snowpack)?  If so, should I just look on Amazon?

I wrote a book for my Level I class (which I am no longer teaching), but have never published the book for general consumption - although it is something I've occasionally considered.