This advisory expires in 24 hours

BOTTOM LINE:

Low hazard level with pockets of moderate. Natural avalanches are unlikely, pockets of human triggered avalanches possible.

TREND:

Stable.

DISCUSSION:

The last major wind event is still showing its colors at Hatcher. Wind stripped ridgelines covered in tundra hold only a few inches of snow and swollen bowls and gullies are loaded with over 7 – 11 feet of snow. Some powder exists in the most protected areas, but the landscape is dominated by soft and hard slabs, sastruggi, grass, crusts, sand boxes (facets).

A really general statement would be that the North aspects are loaded with snow and the Southerlies are stripped, thin and faceted. While North aspects show good stability, South shows a very weak structure that could be problematic in specific, small areas where wind slabs exist on top of the faceted substructure.

A future problem could be intense sun radiation breaking down the Southern aspects structure and releasing wet slides naturally or with your assistance. With cloudy weather in the future this is not likely. If the weather goes code blue with warm temperatures steer clear of rocky areas and slopes with a high solar angle of incidence.

Be aware that aspect is not a good tool for generalizing stability or conditions at Hatcher Pass this season. The wind, which has been much more resourceful than the sun so far this season, has not behaved according to aspect. Variability is extreme, so personal evaluation of the conditions is even more critical.

As mentioned already, the snowpack is wildly different from the thin, wind stripped areas to the thicker deposition zones. Fortunately, even these differences do not warrant major avalanche concerns. While the structure of the snowpack is moderate to poor, the strength is generally high and the energy is low. Again, the points of concern are wind deposited slabs up to a foot thick on gully sidewalls and near ridgelines. These have already avalanched on Marmots West face, and some thinner 2-5 inch thick slabs near Rae Wallace ridgelines. Wind slabs up to 5 inches thick were sensitive to skiers weight today on loaded gully sidewalls, but were sporadic and small in volume and scale.

–Jed Workman, Allie Barker

This advisory expires in 24 hours

BOTTOM LINE:

Natural and Human triggered avalanches are unlikely at 2500′ to 3000′ feet.

Natural avalanches unlikely, human triggered possible in pockets of wind loaded slabs at 3000′ to 5000′ mostly on freshly loaded Southerly aspects.

TREND:

Increasing stability.

DISCUSSION:

Winds have hammered Hatcher making it difficult to find good soft consistent snow to ride. Lower elevation willow fields are the only areas that were protected from the winds. Sastruggi, hard slabs, and patchy sun crusts abound.

Winds last week moved significant amounts of snow onto North aspects. The snowpack quickly adjusted to the new load over the weekend and resulted in good stability.

This week we saw a brief wind event move some of the available snow on these North aspects back over to the Southern aspects by ENE winds. These new slabs are 10-15cm thick and are not very reactive. The chance of triggering these slabs exists due to thin, poor underlying structure. If you trigger and avalanche expect smaller scale slabs.

Strong gusting winds have scoured ridges down to tundra and filled bowls and gullies. Some gullies are filled in with very thick hard slabs. These are not likely to be triggered, however, use common sense and avoid these if possible. Many flush into nasty terrain traps compounding the risk.

The sun is starting to effect the snow more and more as daylight hours increase. Sun crusts exist. These would be good layers to watch for the future. Faceting around the crusts exists and when buried by future storms could become an active weakness.

Three point releases were observed on South to Southwest aspect at around 4500′ in the Pinnacle area .  One of these point releases pulled out a small slab approximately 50 feet wide and ran 30 feet. This occurred in a loaded bowl feature where sun radiation was strong. If temperatures warm into the 30′s and/or strong sun radiation heats the snowpack expect to see more point releases and for the shallow instabilities [especially in thin snowpack areas] to become more tender.

A few inches of new snow will improve the conditions substantially and the snowpack is stable enough to handle it, so pray for more snow, and of course, as always, less wind. There is a good chance for total accumulation of 1-2.5 inches of snow overnight and into tomorrow. Temperatures should range 23F to 32F at 4000′ through Sunday, so a chance of rain showers exists.

–Jed Workman, Allie Barker