Posts Tagged ‘snowpack’

Why does the snow sparkle so?

Saturday, January 7th, 2017

Lately around here we’ve been blessed with decent snow cover. A nice change from the last two winters. Nice fresh show that stays fresh thanks to lack of warm surges. To add to the beautiful scene, the snow has had lots of sparkles of light reflecting off the surface from the bright moon or nearby lights (there’s plenty of time to see this with days still solstice short). Here’s a couple photos (click on them for larger versions).

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Why so sparkly lately?

The answer is not in the snow itself, but what happened to the snow after it fell. It is true that normal snow crystals can and do sparkle, but the really big sparkles we’ve seen take bigger crystals… in this case frost crystals that have formed on the snow over a few days. This sort of frost is called surface hoar, ie., hoarfrost that has formed on the surface of the snow. Check out the daytime photos (of the same snow in the upper photos) that show the detail. One clue is the small amount of frost on the alder twig in the second photo.

20170104_150625-reduced 20170104_150715-reduced Hoarfrost in general tends to form during light wind situations when there are cold surfaces and lots of water vapor to crystallize onto those surfaces. The most rapid frost formation occurs when there is a source of liquid water close by such as a stream or fog. Yes, we did have some fog in Haines over the last few days. Uncommon during cold weather at this time of year…because the calm winds which allowed the fog to form are uncommon during cold weather here. Note for backcountry travelers: New snow over surface hoar can create a weak layer in the snowpack and increase avalanche danger.

Iditasnow update & more snow rollers

Friday, March 16th, 2012

Haines beach volleyball court

Since the leap day checkpoint report, most towns have slowed their snowfall pace. Haines and Yakutat, however, have been running hard, each having added an impressive 50 inches this first half of March.

The Top Ten as of 15 March

place town total through 3/15 % of average % of record current depth
1 Haines 357.1” (9.08 meters) 243 116 61” (1.55 m)
2 Yakutat 313.3 (7.97) 218 78 85 (2.16)
3 Kodiak 134.9 (3.43) 196 84 12 (0.31)
4 Barrow 65.0 (1.65) 172 83 13 (0.33)
5 Anchorage 129.4 (3.29) 158 97 34 (0.86)
6 Juneau 130.5 (3.32) 151 66 Trace
7 Haines Customs 342.6 (8.72) 131 93 95 (2.42)
8 Valdez 426.0 (10.84) 131 76 87 (2.21)
8 Kotzebue 78.1 (1.99) 131 65 54 (1.37)
10 Cold Bay 87.7 (2.23) 120 76 23 (0.59)

Remember, the standings are based on snowfall this season compared to the station’s average yearly snowfall. (No, I did not come up with this rating scheme to just to put Haines in the lead). (more…)

Not the last great Alaska snow race

Saturday, March 3rd, 2012

Today is the start of the world famous Iditarod trail sled dog race (“the last great race”), so I thought maybe I should give an report on another (unofficial) great race: the Alaska snow race. It has been a very snowy winter in many parts of Alaska and there is plenty of talk and a little bragging and comparing between towns, so why not make a little fun of it? In no way am I wanting to make light of the real hardships experienced in places like Cordova and Valdez, where schools were closed for more than an isolated “snow day” due to fears of structural failure of school buildings, among other problems. Believe me, I understand the issue of dealing with tons of snow, since I live in one of the major league snow towns (Haines). What I want to do is compare details of a longer list of places facing heavy snow this winter, and look at why. First the standings, as of the leap day checkpoint: units are inches for snow and feet for elevation.

table

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How dense is snow?

Friday, February 17th, 2012

The huge section of heavy old snow pictured below finally slid off the roof of our shed sometime in the middle of the night recently. Luckily, it remained jammed vertically in the snow below and did not fall against the shed. What do think it weighs? Click on the photos for a better look…it’s the same berg from opposite ends.

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It would not be hard to estimate the weight of this thing if we knew its density. And you might want to know the density your snow for a variety of reasons. One of the more common reasons is to figure if the weight of the snow might damage something. Check out the scene from our school a couple weeks ago: (more…)