Haines Avalanche Center

Forecast Expired - 11/21/2021

Above 2,500ftHigh

1,500 to 2,500ftHigh

Below 1,500ftConsiderable

Degrees of Avalanche Danger

Avalanche Problems

Problem 1

Storm Snow:

Most areas received 6-10″ of new snow in the last 1-2 days, and heavy snow is expected to continue today. Storm totals could be 10-20″ by tonight. The snow is light, dry, and powdery, which is good, but there may also be a freezing rain crust within last night’s new snow. This crust will likely exist up to mountaintop level.

Anywhere the winds have been moving the new snow around you will find fresh hollow wind slabs that will be sensitive and poorly bonded. Natural and Human Triggered avalanches are likely today in terrain steeper than 30 degrees. Safety can be found in dense trees, and low-angle slopes.

 

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Problem 2

Persistent Slab:

 

Confidence: Low-Moderate

Elevation: From 2,500ft to 4,000ft

Our alpine snowpack in all zones contains one or more rain crusts from mid October. Weak facetted snow has formed above and below the crust, and has been found to be quite sensitive to the weight of our new snow. Any steep, open pockets of snowpack will be ripe to avalanche on this layer, about 30-60cm deep. We expect this October rain crust will be a lasting problem as we go into winter so keep your guard up! This layer exists on all aspects, but observations are limited and uncertainty is high.

 

What is the best way to manage this risk? We can simply avoid alpine terrain that is about 30 degrees and steeper. Be aware that venturing on these steeper alpine slopes is relatively high risk currently. Persistent slabs require a wide safety buffer.

Another way to reduce your exposure to these deep weak layers would be to stick to areas of deeper snowpack (>1m deep). But be wary of hidden rocks that can act as trigger points, and thin areas around the margins of a slab.

 

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Weather

October brought in heavy snow in the alpine, followed by a few rain/sun crusts. November was mostly dry until mid month, when 24-30″ of snow fell.

10-20″ of new snow is likely Saturday night-Sunday night, with moderate to strong NW winds. There also could be a period of freezing mixed in Saturday night. This could create a new ice crust within the storm snow even up to mountain top elevations.

 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   40″  8″ / 0.40*  11″ / 0.55*   0′  strong, N  7″ / 0.40*
Flower Mountain @ treeline  43″  7″ / 0.30  7″ / 0.30  0′ strong, NW  7″ / 0.30*
Chilkat Pass @ 3,100ft  25″  4″ / 0.20  9″ / 0.40  0′ strong, NW  4″ / 0.20*

( *star means meteorological estimate )

Additional Information

In November, onX Backcountry is donating $10 of every membership to support forecasting. By leveraging their Slope Angle and Avalanche Forecast layers you’ll have access to the tools that help  inform safer backcountry travel this year.


 

Practice like you play. Make sure all your rescue gear is fully functional and your beacon has NEW 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.

 

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