Hatcher Pass
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The Bottom Line
It will be possible to human trigger or remotely trigger a persistent slab avalanche today at all aspects and all elevations, 1-4 feet deep. Natural avalanches are unlikely. Warmer springtime temperatures today will make it possible to trigger small wet-loose sluffs, on steep slopes, on SE to SW aspects in the afternoon. After a big week of storms, an avalanche fatality, an avalanche that crossed the road, and now bluebird skies…we recommend using heightened avalanche awareness skills, evaluating snow and terrain carefully, and safe travel protocol today.
Special Announcements 
This avalanche forecast is brought to you by sponsors from the City of Palmer.
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| 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. |
A big storm on 3/7- 3/9 deposited about 35″ of new snow and almost 3″ of water at 3550′. This rapid load contributed to an avalanche cycle, mostly occurring mid-storm.
The tragedy of the week was the avalanche accident and fatality on the 16 mile run, on a S aspect at 2000′. This avalanche was a large soft slab on a small slope that funneled into a terrain trap/creek bed. The terrain trap significantly compounded the size of the avalanche. A preliminary report has been done and a complete report will follow.
16 mile avalanche fatality investigation Credit: CNFAIC
Location of the 16 mile avalanche
Location of the human triggered slab avalanche, from higher up on the road run. 3/10
3/9 16 mile avalanche SS-AR-D2-O
Avalanche on Marmot that crossed the road 3/12. We suspect a remote trigger.
Another view of avalanche on Marmot that crossed the road 3/12.
| 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 |
Persistent slabs will be possible to human trigger, 1-2 feet deep, on all aspects, and all elevations. 35″ of light density on 3/7-3/9 has settled 15″, increasing the density of the slab. Observers have found this slab to be sitting on a faceted layer. With limited information, we have reason to believe that many of the recent avalanches failed on this upper persistent slab layer.
arrow on the right shows slab avalanche from 3/12. arrow to the left is a new slab triggered during avalanche mitigation on 3/13.
| 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 |
Deep persistent slabs will be possible to trigger today up to 4 feet deep on all aspects and all elevations, most likely on E to W aspects below 3500′. It will be hard to find the “spot” where you can trigger the slab. Remote triggers will continue to be the most likely trigger, and possible from 1/4 mile away. Although many will ski/ride without incident today, this problem is still lingering and we recommend not letting your guard down.
Check out this near miss video from 3/12 here to see how far avalanches are being remotely triggered from.
Below is a video showing poor structure and high propagation of the buried January Facet layer at the 16 mile accident site, S aspect 2000′. This layer will become more of a problem with a significant warm up.
Safe travel habits like travelling one at a time, especially on wide open, broad terrain features, utilizing islands of safety, spotting each rider from a safe place, and staying out of the runnout of avalanches from above are all techniques that will increase your safety factor.
Drummy, stiff snow, overlying softer, weak snow is also a good indicator of the problem, however in some cases the weak layer is so deep you probably wont know its there without probing or digging.
| 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 |
Spring is here! March is that time of year when the sun shines bright and we start seeing wet avalanche activity, especially after months of deep dark cold. As of 5am it is 21°F at 4500′. It will be possible to human trigger a wet-loose sluff today on steep slopes, in the afternoon, on SE to SW aspects. Pay attention to time of day and stay off slopes if you see rollerballs and signs of significant warming. If the warming trend continues into the 30’s next week, as forecasted, expect the hazard for wet loose to rise.
