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The avalanche danger is MODERATE above 1,000′. Strong easterly ridgetop winds today are expected to build fresh wind slabs, up to a foot thick, on leeward slopes and in cross-loaded gullies. Watch for fresh wind deposited snow. Additionally, on the southern end of Turnagain Pass, there is a remote chance that a large avalanche could break near the ground.
The avalanche danger remains LOW below 1,000′.
SUMMIT LAKE: The snowpack is only 3-4′ thick in this area and weak faceted layers sit in the mid and base of the pack. Above 2,500′ there is still a chance a person could trigger a large avalanche and extra caution is advised.
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. |
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 |
I hate to say it, but it looks like a wind event is on the doorstep. Weather models are forecasting easterly ridgetop winds today to be in the 30-40mph range with stronger gusts and even increase into the 50’s mph tomorrow. If this verifies, we can expect fresh wind slabs to be forming. Winds also have a chance at making it into the trees, but we can cross our fingers it doesn’t ruin too much of the good riding conditions. Interestingly enough, only a few inches of snow at most should accompany the winds, so new slabs will primarily be composed of the existing loose snow on the surface.
For today- watch for active wind loading and any stiff snow over softer snow. Cracking in the snow around you is a sure bet you’ve found a slab. It should be relatively easy to suss out any new wind slabs as conditions should be changing in front of our eyes through the day. Areas spared from the winds have a generally LOW avalanche danger.
Winds transporting snow along the top of Tincan’s Hippy Bowl yesterday. 12.11.20. Photo: Eric Roberts
Plenty of loose snow on the surface to blow into slabs… The good news, the new crop of surface hoar will hopefully get blown over ahead of the next snowfall event. 12.11.20. Photo: Alan Abel
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 the higher Alpine elevations on the southern end of Turnagain Pass and in the Summit Lake area, we are still concerned about the weak facets on the ground. These areas have a much shallower and weaker snowpack than the core of Turnagain Pass. In order for an avalanche to be triggered, we need a slab as well as a weak layer. Elevations below 2,500′ the pack is littered with mid-pack crusts and is lacking that ‘slab’, at the higher elevations it’s not necessarily. Hence, if traveling in the higher terrain be suspect of a hard shallow snowpack over weak snow where a deep slab could be lurking.
Regarding the mid-pack faceted layer that sits 1-3′ below the surface (below the last storm snow from Dec 6-7), this continues to show bonding and good stability. This is a layer we were watching for the past few days.
Yesterday: Mostly blue skies were over the region. Winds along the ridgelines were from the east in the 10-20mph range with gusts into the 30’s mph after sunset. Temperature were in the single digits in creek bottoms and warmed to near 20F at 1500′ above the inversion.
Today: Clouds, wind and some slow flurries are moving in as a front passes over associated with a low-pressure system in the Gulf. Ridgetop winds are expected to increase from the east up to 40-50mph with stronger gusts. Only a meager amount of snow is expected, up to an inch at most today and a couple inches tonight. Temperatures should remain just cool enough for snow to sea level.
Tomorrow: Strong easterly winds are expected to remain through tomorrow with little chance for precipitation. Skies do have a chance for some clearing along with the strong winds. A better chance for snow is headed in on Monday.
PRECIPITATION 24-hour data (6am – 6am)
Temp Avg (F) | Snow (in) | Water (in) | Snow Depth (in) | |
---|---|---|---|---|
Center Ridge (1880′) | 19 | 0 | 0 | 62 |
Summit Lake (1400′) | 10 | 0 | 0 | 24 |
Alyeska Mid (1700′) | 21 | 0 | 0 | 57 |
RIDGETOP 24-hour data (6am – 6am)
Temp Avg (F) | Wind Dir | Wind Avg (mph) | Wind Gust (mph) | |
---|---|---|---|---|
Sunburst (3812′) | 17 | E | 15 | 37 |
Seattle Ridge (2400′) | 19 | SE | 13 | 26 |
Date | Region | Location | Observer |
---|---|---|---|
10/27/24 | Turnagain | Observation: Tincan | Michael Kerst |
10/21/24 | Turnagain | Observation: Turnagain Pass Road Observation | Trevor Clayton |
10/19/24 | Turnagain | Observation: Tincan – Below Todds Run | Andy Moderow |
10/18/24 | Turnagain | Observation: Taylor Pass | Eli Neuffer |
10/15/24 | Turnagain | Observation: Tincan Common | John Sykes Forecaster |
10/14/24 | Turnagain | Avalanche: Tincan | CNFAC Staff |
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 |
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