What is Remotely Triggered Avalanche?

Sadly two sliders died recently in an Aspen, Colorado avalanche in Moderate Avalanche Conditions, even after checking reports and digging a pit.  It is possible that they were doing a zig-zag traverse.  Apparently, they first remotely triggered avy #1 several hundred feet away and then got caught in avy #2. 

The Colorado Avalanche Information Center did a remarkable job of releasing what looks like a full report so quickly: 
avalanche.state.co.us/Accidents/Colorado...+Season/20070313.htm

However, I am mystified how on could remotely trigger an avalanche at what looks like a thousand feet away?   Does anyone have a fix on how remote triggering works?

The report on wildsnow seems to indicate the first slide occured as a natural release, and then the skiers continued up the more treed section of the slope? I obviously have no other info, just repeating heresay. I've never seen a report of a "remote triggered" event before. The McClung/Schaerer Avi Handbook doesn't mention it anywhere....

???

Maybe causing a failure somewhere away from the top of the path? Like sending a crack uphill resulting in slab release?? Imagine skinning down low, loading the pack and causing a failure that travels uphill just to slide down on you? Best guess...no idea.

Well... I did find this:

www.avalanche.org/~uac/encyclopedia/remote_trigger.htm

Remote Trigger:

Someone does not need to be on the avalanche to trigger the avalanche. Especially in a snowpack with high propagation potential, a person can initiate a fracture from some distance away. We call these “remote” triggers. It’s common to remotely trigger an avalanche from the ridge above a slope, a gentler slope next to the avalanche and especially from a flat or gentle area below the avalanche. Needless to say, if you remotely-trigger an avalanche, the snowpack is extremely unstable and you need to choose your routes very carefully.

However, looking at the photos, I am still puzzled as to how that worked.  The distances seem so great.  Notice that the quote says that the snowpack would be extremely unstable.  I think if things were that unstable, I wouldn't be there.  This concept of remote triggering has given me more to think about.

If there's a layer in the snowpack under tension and stiff enough to crack, a crack can be started at one point and propagate at high speed to another point, steep enough or wind loaded enough to let loose a large slide. I've seen it happen - for instance near Rogers Pass , when one of our group took a single step out of the trees to a corner facing a steep bowl 1/4 mile away, it triggered the bowl. It would be easy in such conditions to release a slide on top of you or on top of another party. I've seen it develop that way in the spring. Cold newfallen powder can be topped by new corn snow and thus look innocent, but be treacherous.

The conditions for long distance triggering tend to be much more ripe in the Rockies than around here (not to say it can't/doesn't happen here, but no surprise this account is from CO). So at any rate, it's not something most of us would generally have a "feel" for from observing our typical Cascade conditions alone.