Archive for the ‘Weather Related’ Category

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.

Precipitation patterns & perceptions

Saturday, October 22nd, 2016
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Pick-up soccer on the Haines school sports field on 30 Sep 2106. Most years the field or the weather are not in too good of shape at this time of year.

Of all the weather elements, precipitation seems the most chaotic when it comes to spatial and temporal patterns. In reality, I think wind is probably more variable over both time and distance, but I guess we must understand that, since we don’t talk about it nearly as much as peculiar precipitation patterns such as long wet or dry periods, heavy precipitation events, adjacent areas getting very different amounts or types of precipitation, etc. When do these peculiarities rise above perception and prove to be truly unusual? (more…)

Are you SAD yet?

Monday, November 9th, 2015

Everybody is different, but the reduced light in the North and the gloomy weather in many parts of Alaska at this time of year affect almost everyone to some degree or another. Seasonal Affective Disorder (SAD) is the fancy name for the winter blues, bad weather blahs, cabin fever, hibernation instinct…fill in the blank with your term. If you are not familiar with the phenomenon, here’s the Mayo Clinic’s briefing.

hours of sunup on Nov 15th

November 15th potential sunlight

Daylight

Northern areas have much shorter days than more southerly parts of Alaska or elsewhere at this point in the winter, but there are mitigating factors helping them: longer twilight morning and evening, fewer clouds and more reliable snow cover to reflect available light and provide contrast. (more…)

Celebrating the end of the snow drought

Tuesday, February 3rd, 2015

happy skierWhile some folks back east may have been mightily inconvenienced by recent snows, here in Alaska most people like to see a little snow in the winter. This winter many of us have seen very little. Here in Haines, one of the snowiest sea level towns anywhere, things were looking pretty brown until last week, when we got almost a foot of nice light snow. You could almost hear the relief around town, as folks got back into the swing of snow removal, or dusted off their skis. My family did both, plus made a batch of snow ice cream. (Never made snow ice cream? Strangely, as a meteorologist, Alaskan, skier, etc, I’d not even heard of it for my first 20-some years in Alaska! I was going do a whole post on snow ice cream but discovered it’s not the novelty I thought it was…just Google it.) (more…)

Sea breezes: an Alaskan spring-summer staple

Friday, May 30th, 2014

You’ve heard it said…Alaska has sooo much coastline… We do, about 34,000 miles (54,700 km) worth, and we have the perfect weather phenomenon to go with it: the sea breeze. The sea breeze is a local wind blowing from water to land arising from the relative warmth of the land vs. the water. Warmer land leads to rising and/or expanding air and lowers the surface pressure, drawing in the cool  air off the water. It is not unique to Alaska–It is found (more…)

Alaska weather on a roller coaster

Tuesday, February 11th, 2014

Wind-blown dust in Haines and other places.

forecast-map

Red flag wildfire danger for the Mat Valley.

Strong pressure gradient along coast.

Back into the freezer

The strong “January thaw” that pushed well into the interior and tied the all time January record for Alaska is being pushed toward the back of our memories by seasonal and colder weather. Boy, it feels colder after a long warm spell! Wind chills here in northern Southeast Alaska are bouncing down to 5 to 15F below zero (-20C to -26C) at times. (more…)

Signs of Spring in Alaska

Monday, March 25th, 2013

We’re a few days into Spring, at least according to astronomers. Last Wednesday (3/20) was the Vernal (Spring) equinox–equal night, equal day. While the flowers may be blooming many places in the Lower 48, such traditional signs of spring are a long way off here in the frozen north. But here are a few signs of the season for this equinox time of year in Alaska: (more…)

The power of the sun

Saturday, January 12th, 2013

Although the world apparently did not end on Dec 21, 2012 the date triggers strong feelings for most Alaskans every year. Of course it is because it marks the winter solstice…the shortest day of the year…and the promise of longer days ahead. It’s a few weeks past the solstice before most Alaskans notice any change, and even longer for the increasing solar radiation to have any noticeable effect on the weather. So, congratulations, we’re about at that point, and in my psychological bag of tricks for keeping upbeat through the Alaskan winter, it is the point beyond which things have got to just keep getting better. My advice is to get outside as much as possible and ingest some of the increasing daylight. At this point in the cycle (January 12th) here are the daylight stats:

city day length (hr:min) daily change (hr:min)
Barrow 0:00 n/a
Kotzebue 3:45 +0:08
Fairbanks 4:54 +0:06
Nome 5:02 +0:05
Anchorage 6:16 +0:04
Bethel 6:22 +0:04
Juneau 7:00 +0:03
Kodiak 7:08 +0:03
Ketchikan 7:37 +0:03
Adak 8:13 +0:02

(more…)

Why is it so cold in Glennallen?

Wednesday, December 19th, 2012

The question in the title came to me in an email, but for every email I get there are probably hundreds asking the same question in Glennallen. Sure, there are thousands more asking it about where they live, be it Fairbanks or Juneau or Orlando for that matter. But I want to look at what appears to be a unusually cold spot this winter, the capital of the Copper River Valley, population, after throwing in close neighbors Gulkana, Gakona, Copper Center, etc, of a 1,100 or so very tough Alaskans.

Let’s look at the weather depiction map from yesterday Morning, courtesy of the Alaska Aviation Weather Unit. A great example, as Gulkana (that’s where the weather station is located), labeled with its 4 letter code PAGK, was the colder than any station except Northway (PAOR)! It was 40 below (Fahrenheit or Celsius, take your pick), colder than Fairbanks at the time and most of the rest of those off the map to the north. Those around it are way warmer, with only Eureka (PAZK) being in the same ballpark. Talkeetna (PATK) and Anchorage (PANC) are not even below zero! Are not all these places in the Southcentral zone?

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Termination dust waits for no one

Tuesday, August 28th, 2012

When I moved to Alaska in 1982, I was a real cheechako. I did not even know what termination dust was. The term was never mentioned in meteorology school. It does not appear in the meteorology glossaries of the NWS, American Meteorological Society or the Weather Channel, nor is it in Wikipedia. Back then it was a bit of an initiation for new arrivals to figure out what the others were talking about. Here are a couple recent examples, taken Tuesday evening, August 28th. (I back-dated this post a few days to that date.)

Looking west from the Haines High School track. (more…)