Haines Avalanche Center

Forecast Expired - 04/25/2021

Above 2,500ftConsiderable

1,500 to 2,500ftConsiderable

Below 1,500ftConsiderable

The Avy Rose shows the forecasted danger by elevation and aspect.

It adds more detail about where you are likely to find the dangers mentioned in the forecast. The inner circle shows upper elevations (mountain top), the second circle is middle elevations, and the outer circle represents lower elevations.

Think of the Rose as a birds-eye view of a mountain, looking down from above. The rose allows our forecasters to visually show you which parts of the mountain they are most concerned about.

WNWNNEESESSW

Degrees of Avalanche Danger

Avalanche Problems

Problem 1

Wet Avalanches:

Confidence: High.     Distribution: Scattered on solar aspects, isolated on shaded aspects.   Sensitivity: Reactive.

 

We are now into a pattern of daily freeze/thaw cycles, which is good for our snowpack. This cooler weather has helped to reduce the amount of natural avalanche activity this week. If you’re out in the early morning, things are likely to be frozen and stable. But as the temperature climbs in the afternoon, the danger will rapidly rise — especially on SE-S-SW-W aspects. Natural and Human-caused wet slides are likely during daytime heating on solar aspects steeper than 30 degrees. Some of these slides could be deep and destructive.

 

Our snowpack contains several rain/sun crusts, and a few old weak layers that will continue to weaken as the snowpack becomes warmer, softer, wetter, and weaker. Solar heating will cause water to percolate through the snowpack and run along crusts, which lubricates the layer.

 

If you travel in the mountains, do so in the early morning, before the snowpack heats up. When the snow softens to ankle-deep, it’s time to move to safer slopes. Keep an eye on the weather stations. If we do not get a solid freeze overnight, expect increased wet slide activity and high danger the next morning. Rocky areas will be common places for wet slides to be triggered.

 

Even small wet slides can easily entrain a person and carry them into a terrain trap.

 

 

Likelihood:

  • Almost Certain
  • Very Likely
  • Likely
  • Possible
  • Unlikely

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Problem 2

Falling Cornice:

With all this sunshine, warmth, and a whole winter’s worth of cornices built up, you should expect any snow ledges or cornices to be dangerous right now. Stay WAY back from these monsters, which are common along ridgelines and summits. Stay out from underneath any slopes that have cornices hanging overhead. They may collapse on their own at any time, or be triggered by human weight on top.

 

Likelihood:

  • Almost Certain
  • Very Likely
  • Likely
  • Possible
  • Unlikely

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Avalanche Activity

This D3 wet slab occurred 4/19 at 2pm. Transitional zone, Takhin ridge, (E aspect at 2800ft) Photo: Erik Stevens.

 

We had a major wet slide cycle 4/16 – 4/20 under record high temperatures. Things have cooled off drastically since then, but south aspects are still getting cooked.

Weather

Temperatures have cooled since last weekend. We are now getting solid overnight freezes in the mountains, and daytime temperatures are reaching the mid 30’s during the day above 4000ft, under north winds and sunny skies. This weather will continue through the weekend, though the winds may let up, which would help to heat up the snowpack somewhat during sunny afternoons.

 Snow Depth [in] Last 24-hr Snow/SWE [in] Last 3-days Snow/SWE [in]  Today’s Freezing Level [ft]  Today’s Winds Next 24-hr Snow/SWE
Mount Ripinsky @ treeline   130″+*  0″ / 0.00* 0″ / 0.00*   0′  light, var 0″ / 0.00*
Flower Mountain @ treeline  94″  0″ / 0.00 0″ / 0.00*  0′  light, var 0″ / 0.00*
Chilkat Pass @ 3,100ft  49″  0″ / 0.00 0″ / 0.00*  0′  light, var 0″ / 0.00*

( *star means meteorological estimate )

—The Mt. Ripinsky weather station is completely buried and no longer reporting.—

Additional Information

Practice like you play. Make sure all your rescue gear is fully functional and your beacon has full batteries. Make sure 1) everyone in the group has a functioning beacon, shovel and probe 2) knows how to use them and 3) has trained in companion rescue in the last year. Keep your skills fresh. If you head into the hills, watch out for red flag avalanche conditions, natural avalanches, whoomphing or collapsing, and shooting cracks.

 

Education Video Links:

Announcements

We’re hiring for a part-time Avalanche Forecaster for winter 2021-2022. Click here for more info.

This will be our last update of the season. Click the + Full Forecast link below for each zone to read more. Thanks to all of our supporters, contributors, and sponsors for a great season!