June Snowfall on Mauna Kea, Hawaii

I glanced at the webcams located atop 13796' Mauna Kea in Hawaii a couple of hours ago, and was shocked to see fresh snowfall. Too bad it's melting fast, almost gone now:

mkwc.ifa.hawaii.edu/current/cams/index.cgi

Like the Pacific Northwest, snowfall in Hawaii shows a strong positive correlation to La Nina. But getting a few inches of snow at 13000 ft there in June is very unusual, just as it is to get a few inches down to 3000 ft here (or to get 40+" as Paradise has gotten so far this month).

Wow! No way! Thanks for sharing that Amar...it's actually quite funny, one of my co-workers and I surf frequently and I told him there's not many places you can live in the world and be able to surf and ski year round. Then we contemplated moving to Hawai'i. ;D

Cool; I was just reading about Mauna Kea on your web-site, very interesting reading about the 3000'V of possible skiing, not too bad. I think I'll have to bring my skis if I ever go to Hawaii.

I am a little surprised to learn that neither of the Hawaii giants host any glaciers, I would think that given the abundant precipitation, and the lofty elevation, there should be at least a small glacier.

Just doing a little research, Chimborazo--(some regard Chimborazo as the "highest" mountain in the world because it is the highest mountain in the region, and it's located just 100 miles south of the equator, putting it's summit further away from the center of the earth than any other mountain). Chimborazo's glaciers end at an elevation of ~15000', almost 1500' higher than the Hawaii summits, but the Hawaii volcanoes are located 1500 miles north of the equator; not all that significant of a difference, but perhaps enough. The lowest reaching glacier in the Himalayas is 4000(~13k') according to  www.sciencedaily.com/releases/2007/03/070327113346.htm . The Himalayas are located less than 10dg north of Hawaii.

I am a little surprised to learn that neither of the Hawaii giants host any glaciers, I would think that given the abundant precipitation, and the lofty elevation, there should be at least a small glacier.

Well, there used to be a large Pleistocene ice cap atop Mauna Kea, over 27 sq miles in size and reaching down as low as 10500 ft, marked by numerous large moraines. Most likely there was one atop Mauna Loa too, although all evidence there has been buried by subsequent lava flows. See hvo.wr.usgs.gov/volcanowatch/2007/07_10_18.html and this book excerpt .

But the reason that there are no glaciers now is that there is NOT any abundant precipitation. The region near the summits of Mauna Kea and Mauna Loa (and to a lesser extent, Haleakala) is a desert. That's what makes all three of them into ideal locations for astronomical observatories. The east and NE facing coastal areas of the Hawaiian Islands receive tremendous precip, averaging over 300" per year in several locations, but the summits of Mauna Kea and Mauna Loa average closer to 10" of precip per year, much of it in the form of winter snowfall.  See this precip map, where the two driest spots on the Big Island mark the summits of Mauna Kea and Mauna Loa:

www.worldatlas.com/webimage/countrys/nam...hermaps/hiprecip.htm

Why is this so? In the tropical oceans, there is something known as the "trade-wind inversion", which is a temperature inversion layer sitting between the moist easterly surface winds (the trade winds) and the dry westerly winds at higher elevations. This inversion layer caps off the clouds and moisture, and holds them far below the summits (generally below 6000-9000 ft), similar to the "sea of clouds" phenomenon which is so common in the Cascades during periods of onshore flow and which is also caused by an inversion layer capping the clouds (temporarily). The air above the inversion remains clear, dry, and stable, in a smooth laminar flow (low-turbulence) which provides good "seeing" for the observatories.

The tropical inversion generally lasts year-round, but varies in strength being weakest in the northern hemisphere winter. It is also subject to breakdown locally, as when the southerly parts of mid-latitude storm systems reach down to Hawaii and mix the atmosphere across all layers. This pattern is what brings snowfall to the summits of the high Hawaiian volcanoes, sometimes as much as a couple of feet atop Mauna Kea during a major winter storm. 

Seriously, reading your guys' threads and replies is like going to science class with an awesome teacher at the helm! Informative and entertaining!

Very interesting precipitation maps, do you have one for Washington? I would imagine there would be similar contrast - from the Olympics to eastern Washington.

I wonder why convection, does not punch through the inversion layer more often and create thunderstorms that might effect the volcanoes.

Sounds like Hawaii gets slammed by a hurricane every few years, I wonder if the freezing levels associated with such tropical systems would be too high for snow on the summit regions. This was a question I failed to ask senor Reyes when I went to the 18,700' Pico De Orizaba (www.turns-all-year.com/skiing_snowboardi...dex.php?topic=5783.0), which also gets hit by hurricanes and other tropical systems.

I lived in hawaii for a short time but never got to ride there....too much surfing to be done. I went and visited a friend on the big island this winter. When I got off the plane they had gotten a couple of feet on the mountain over the previous days. Funny how its free to fly with skis or a snowboard but it costs a $100 each way with a surfboard. I should have brought the split seeing as it was flat. I can't imagine what they would charge you to fly with a surfboard nowadays.