Each low-pressure event impacting our area over the past week seems to be bringing slightly warmer temperatures than the last; today will be no exception. As temperatures increase, the rain/ snow line may reach as high as 2,000’ as this next bout of weather impacts the eastern Kenai Peninsula this weekend. What does this mean for avalanche activity today? It means that rain on snow may initiate natural avalanches in the treeline elevations where we’ve seen mostly snow for the past 3+ days. Any avalanches today will be large and un-survivable as storm slabs alone are 2-3’ deep. Add winds to that or the potential for an avalanche to step down into weaker layers deeper in the snowpack and we’re flirting with the potential for 5-6’+ deep avalanches.
Though observations and info from the alpine (above) 2,500’ have been minimal since Tuesday, an additional 8-16″ of snow forecated and strong easterly winds over known weak layers and crusts create a serious concern for large and destructive avalanches today. In channeled terrain, debris was running to the valley floor and all the way to sea level in some cases yesterday. Today the message is simple – Avoid all avalanche terrain, this includes slopes steeper than 30 degrees and all runout zones.
South of Turnagain Pass: A brief weather window on Thursday allowed observers to view a plethora of natural avalanches that ran mid-storm. Given a shallower snowpack in these areas, this week’s load is proving generous enough to tip the stress vs. strength balance south of the core Turnagain Pass area. Suspect areas include Johnson Pass, Lynx Creek and Summit Lake.
Debris in channelled terrain in the bottom of east facing terrain at the base of Twin Peaks. Just south of Turnagain Pass. Photo: 3/14.
Storm Totals (Wed 6am – Sat 6am):
Yesterday: Temperatures in the mid to upper 30’s kept rain the dominant precip type below about ~700′. Turnagain Pass (1,880′) only saw ~3 € of wet, heavy snow (.9 € water) as accumulation was barely keeping up with settlement rates. Ridgetop winds were sustained from the east in the mid 30’s €“ 40mph with gusts into the low 70’s at Sunburst.
Today: Temperatures continue to climb into the high 30’s at 1,000′ with the rain/ snow line anticipated to be in the 1,800′ €“ 2,000′ range. On average we can expect another ~1 € of water though areas such as Portage and Girdwood could see more. In the alpine this translates to another 8-16 € of snow.
Tomorrow: The active weather pattern continues as yet another surface low moves into southcentral AK. Expect more rain in the lower elevations, moderate to strong southeasterly winds and ample snow/ whiteout in the alpine. Rain/ snow line looks to be in the 1,800-2,400′ range.
PRECIPITATION 24-hour data (6am – 6am)
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||32||3||.9||102|
|Summit Lake (1400′)||35||0||.2||37|
|Alyeska Mid (1700′)||32||0||.89||89|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||28||n/a *||n/a*||n/a*|
*Seattle Ridge weather station is not reporting reliable wind data at this time.