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Today’s avalanche problem will be Persistent Slab and Dry Loose. It will be possible for humans to trigger and remotely trigger Persistent Slabs at mid and upper elevations on West thru North aspects on slopes steeper than 35 degrees. Small Dry Loose avalanches will be possible at all elevations and all aspects on steep slopes. Natural avalanches are unlikely.
Over the last two days Hatcher Pass has received up to 9″ of new snow at 3550′. As the weekend approaches keep in mind any increase in wind speeds or another significant snowfall will increase avalanche danger.
Yesterday there was a small D1.5 remotely triggered avalanche on Marmot. Be aware of steep slopes above and of terrain traps below. Small avalanches can still be dangerous, especially if they sweep you into terrain traps.
Riding conditions have improved and the drizzle crust has become supportable in some areas.
Hatcher Pass Avalanche Center is running a special online auction for a one-day stand-by heli seat with Chugach Powder Guides. Over the next two weeks you have the chance to show just how much you like HPAC forecasts and heli access skiing or boarding!
Here’s how it works. Visit the “Auction” album on HPAC’s Facebook page between now and March 21, 2021 and place your first bid on the item. The bidding starts at $500. You can increase the bids in whole dollar increments. Check the page regularly and increase your bid if someone has outbid you. The auction will close on March 21st at 8 pm. HPAC will contact the winning bidder. Serious bidders only please.
Numerous dry loose and wet loose avalanches were observed Sunday and Monday. On Wednesday three small slab avalanches were triggered on the west face of marmot.
3/10: Marmot West Face 3800’ click here for more info.
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 |
On 3/10 moderate to strong winds from the southeast, combined with 7” of new snow were able to bury weak sugary snow building slabs 4-12” thick and in isolated areas up to 18”. These freshly loaded Persistent slabs will be found at mid and upper elevations, on west thru north aspects. Human triggered avalanches will be possible and natural avalanches are unlikely.
These freshly loaded slabs are failing on buried near surface facets sitting on the 2/26-27 Drizzle crust. A couple things to be aware of…crust-facet sandwiches are often more dangerous than facet layers. We believe the drizzle crusts and NSF layer to be widespread which will continue to contribute to this problem with additional loading events. This crust has made for a nice bed surface for these avalanches to fail on. Additionally, it will be possible for humans to remotely trigger this avalanche problem.
There are several weak sugary layers that are currently buried in the snowpack. First is the drizzle crust facet combo which is 4-12” from the surface. Below this, In the middle of the pack lies an old weak sugary layer of facets. Near the base of the snowpack sits a layer of facets and depth hoar. Click here to gain a better understanding of layering in the snowpack.
Shooting cracks and whumping are red flags for this avalanche problem. Look for smooth freshly drifted snow overlying weak snow when trying to identify this avalanche problem. Last night’s new snow will make visually identifying this problem more challenging. Pole tests and hand pits will help you quickly identify this avalanche problem.
We recommend using low risk travel techniques, this includes spreading out when traveling uphill or near avalanche terrain. Riding slopes one at a time and stopping and regrouping out of harm’s way. Avoid riding slopes that have terrain traps below.
9” of new snow has fallen this week. This low density snow is capable of producing small dry loose avalanches at all elevations and on all aspects on slopes 40° or steeper. Human triggered avalanches are possible, natural avalanches are unlikely.
We recommend using good sluff management if you decide to step out into steeper terrain. These avalanches will be small but can catch, carry and sweep you through hazards, if not managed properly.
3/07-3/11 New Snow Totals:
Independence Mine: 9” of new snow
Frostbite Bottom: 7″ of new snow
The week started off with clear sky and almost spring like conditions. On 3/07 temps started off in the single digits but by March 8th had risen to the high 20s. On the 3/07-3/08 sunny weather and warm temps were able to warm snow surfaces and create Wet Loose problems on steep southern slopes. Late on 3/09 a storm system moved over Hatcher Pass. By the morning of 3/10 moderate to strong winds from the SE blew for 10 hours, these winds were able to transport some snow. The distribution of the 2/26 crust is somewhat variable, thick and supportable in some areas, thin and breakable in others.
NWS Rec Forecast here.
NWS point forecast here.
State Parks Snow Report and Motorized Access information here.
Independence Mine: 3/07-3/11
|
Temp
|
RH
|
Spd
|
Gust
|
Dir
|
|
|
|
SWE
|
SnoHt
|
|
---|---|---|---|---|---|---|---|---|---|---|---|
Min | 7 | 35 | 0.3 | 1.3 | N | 10.8 | 48 | ||||
Max | 28 | 95 | 7.3 | 16 | N | 12.8 | 56 | ||||
Average | 20.3 | 66 | 3.3 | 6.8 | – | 11.9 | 50 |
Marmot: 3/07-3/11
|
Temp
|
RH
|
Spd
|
Gust
|
Dir
|
---|---|---|---|---|---|
Min | 6.4 | 27 | 0 | 2 | N |
Max | 33.4 | 99 | 19 | 30 | N |
Average | 19.4 | 70.1 | 4.7 | 9.2 | ESE |
Frostbite Bottom: 3/07-3/11
|
Temp
|
RH
|
Spd
|
Gust
|
Dir
|
|
|
|
SWE
|
SnoHt
|
|
---|---|---|---|---|---|---|---|---|---|---|---|
Min | 11 | 33 | 1.2 | 3 | NE | 11.8 | 44 | ||||
Max | 34 | 101 | 10.6 | 17.1 | NNW | 12.4 | 50 | ||||
Average | 24.9 | 67.2 | 4 | 8.1 | – | 12 | 47 |