Turnagain Pass |
Archives |
Today’s avalanche danger is MODERATE. Strong winds yesterday into last night have built wind slabs on top of a snowpack with multiple weak layers near the surface, making it possible to trigger an avalanche a foot deep or deeper. It will be important to recognize and avoid steep, wind-loaded terrain today. The combination of stiff wind slabs on top of weak snow makes it possible that a person could make it out into the middle of a slope before triggering an avalanche, or for multiple skiers or riders to put tracks on a slope before somebody triggers an avalanche.
SUMMIT/SNUG HARBOR/LOST LAKE/SEWARD: Strong winds continue today in these areas, which means the likelihood of human-triggered avalanches remains high and natural avalanches will be possible today. Be extra cautious if you are getting out in these areas.
Hatcher Pass: Dangerous avalanche conditions remain in this area. Large avalanches have been occurring with one covering the road on Sunday. Please keep tabs on the Hatcher Pass Avalanche Center’s website and Facebook page.
Travel Advice | Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. | Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern. | Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding, and conservative decision-making essential. | Very dangerous avalanche conditions. Travel in avalanche terrain not recommended. | Extraordinarily dangerous avalanche conditions. Avoid all avalanche terrain. |
Likelihood of Avalanches | Natural and human-triggered avalanches unlikely. | Natural avalanches unlikely; human-triggered avalanches possible. | Natural avalanches possible; human-triggered avalanches likely. | Natural avalanches likely; human-triggered avalanches very likely. | Natural and human-triggered avalanches certain. |
Avalanche Size and Distribution | Small avalanches in isolated areas or extreme terrain. | Small avalanches in specific areas; or large avalanches in isolated areas. | Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas. | Large avalanches in many areas; or very large avalanches in specific areas. | Very large avalanches in many areas. |
We received reports of several natural and human-triggered avalanches during yesterday’s wind event:
Seattle Ridge: A snowmachiner triggered a large wind slab on a steep, rocky convexity near the Seattle Headwall (photo below). Nobody was caught in the slide.
Seward Highway: Large natural wind slabs were observed along the Seward highway near Girdwood and in the Summit Lakes area.
Snowmachine-triggered wind slab avalanche near the Seattle Headwall yesterday. Nobody was caught in the slide. Photo: Clint Kyffin. 04.05.2021.
Signal Word | Size (D scale) | Simple Descriptor |
Small | 1 | Unlikely to bury a person |
Large | 2 | Can bury a person |
Very Large | 3 | Can destroy a house |
Historic | 4 & 5 | Can destroy part or all of a village |
Strong winds yesterday into last night have formed fresh wind slabs on top of weak snow, making it possible to trigger an avalanche large enough to bury a person today. Although we do not expect to see the same natural activity as we did yesterday, these fresh wind slabs have not had much time to bond to old snow surfaces, and in many places are just waiting for a person to come along and trigger an avalanche. Although the likelihood of triggering an avalanche today is slightly lower than it was yesterday, there are a few factors that might actually make it more difficult to manage this problem today:
Navigating in the backcountry today will require identifying and avoiding recently wind-loaded terrain. Be extra cautious near ridgelines, on the downslope side of steep convexities, and in cross-loaded gullies. Cracks shooting out from your snowmachine or skis, or the ‘whumpf’ of a weak layer collapsing are clear signs that the snowpack is unstable. Wind slab problems tend to be short-lived, but we are still close enough to the latest wind event that a little extra caution is warranted today.
Natural avalanche on a wind-loaded slope in the Summit Lake area yesterday. Photo: Alex McLain. 04.05.2021
Signal Word | Size (D scale) | Simple Descriptor |
Small | 1 | Unlikely to bury a person |
Large | 2 | Can bury a person |
Very Large | 3 | Can destroy a house |
Historic | 4 & 5 | Can destroy part or all of a village |
In addition to the wind slab problem mentioned above, we are still concerned with multiple weak layers that are buried in the upper 3′ of the snowpack. We have been talking about these weak layers for weeks now, and have seen avalanche activity associated with them as recently as last Thursday. Persistent weak layers may have also played a role in the activity in the Summit Lake area yesterday. Although it is becoming less likely to trigger something on one of these layers, they are still capable of producing large avalanches. These weak layers may be a little more sensitive today where they were loaded by wind-transported snow during yesterday’s wind event. This persistent slab problem still requires dialing your terrain use back a notch, avoiding steep and unsupported slopes, or avalanche terrain with traps like rocks, cliffs, trees, gullies, or abrupt transitions in the path or runout zones.
Yesterday: The big story yesterday was the northwest wind event, with sustained speeds of 10-20 mph into last night and gusts at 35-40 mph. Skies were sunny but temperatures remained cool, with daytime highs in the low teens at upper elevations and upper 20s in the valleys. Overnight lows were in the single digits to low teens F.
Today: Northwest winds have died down near Girdwood and Turnagain Pass since yesterday, although they are expected to remain around 15 mph in the Summit Lake area and as high as 20-30 mph near Seward. Temperatures are expected to reach the low teens to low 20s F during the day before dropping back into the single digits F tonight. A few scattered clouds this morning should break up by this afternoon.
Tomorrow: North winds around 5-15 mph are expected to shift to the southeast tomorrow evening into tomorrow night as more active weather enters the area. Cloud cover is expected to increase during the day, and highs are expected in the low teens to low 20s F. Chances for precipitation increase tomorrow night, with a couple inches anticipated by Thursday morning.
PRECIPITATION 24-hour data (6am – 6am)
Temp Avg (F) | Snow (in) | Water (in) | Snow Depth (in) | |
---|---|---|---|---|
Center Ridge (1880′) | 20 | 0 | 0 | 109 |
Summit Lake (1400′) | 17 | 0 | 0 | 48 |
Alyeska Mid (1700′) | 21 | 0 | 0 | 120 |
RIDGETOP 24-hour data (6am – 6am)
Temp Avg (F) | Wind Dir | Wind Avg (mph) | Wind Gust (mph) | |
---|---|---|---|---|
Sunburst (3812′) | 9 | WNW | 11 | 38 |
Seattle Ridge (2400′) | 16 | NW | 10 | 22 |
Date | Region | Location | Observer |
---|---|---|---|
05/13/24 | Turnagain | Observation: Eddie’s, Sunburst, Seattle, Cornbiscuit, Pete’s South | H Thamm |
05/13/24 | Turnagain | Observation: Turnagain Pass non-motorized side | Amy Holman |
05/12/24 | Turnagain | Observation: Warm up Bowl | Tony Naciuk |
05/07/24 | Turnagain | Observation: Turnagain Pass Wet Slabs | A S |
04/29/24 | Turnagain | Avalanche: Turnagain aerial obs | Tully Hamer |
04/27/24 | Turnagain | Observation: Johnson Pass | Noah Mery |
04/23/24 | Turnagain | Observation: Turnagain Sunny Side | Travis SMITH |
04/21/24 | Turnagain | Observation: Bertha Creek | Anonymous |
04/20/24 | Turnagain | Avalanche: Spokane Creek | Schauer/ Mailly Forecaster |
04/16/24 | Turnagain | Observation: Cornbiscuit | Krueger / Matthys Forecaster |
The riding areas page has moved. Please click here & update your bookmarks.
Subscribe to Turnagain Pass
Avalanche Forecast by Email