Haines Avalanche Center

Forecast Expired - 04/11/2021

Above 2,500ftConsiderable

1,500 to 2,500ftModerate

Below 1,500ftModerate

Degrees of Avalanche Danger

Avalanche Problems

Problem 1

Wind Slab:

Confidence: Medium.     Distribution: Specific to wind loaded aspects at elevation (S-E-W).   Sensitivity: Reactive.

 

Recent north wind drifted new snow into sensitive wind slabs. Human triggers are likely particularly at elevation. Moderate to strong winds Friday night to mid-day Saturday transported recent storm snow and deposited it on leeward slopes. These fresh wind slabs are sitting over a variety of old snow surfaces including now buried near surface facets, melt-freeze crusts, and sun crusts. Solar aspects where old sun crusts exist are more prone to slide. Cross loading and top loading adds texture to the snow surface, so keep an eye out of visible loading patterns. Wind slabs often are triggered from shallow areas in the snowpack like rocks, cliffs and vegetation and propagate to deeper areas. Be aware of run-out zones, islands of “safety”, underlying terrain and terrain traps. Solar radiation increases the chance of natural avalanches. Avoid wind loaded slopes.

 

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Problem 2

Storm Snow:

Confidence: Medium.     Distribution: Widespread.   Sensitivity: Stubborn.

 

Recent storm snow on all aspects at all elevations will be reactive to human triggers, as it slowly bonds to the old snow surface and settles out. Human triggers are possible within the new snow, while the trend decreases over time. Keep in mind weak near surface facets that are now buried, or hard melt-freeze crusts provide a smooth running surface for the avalanches to occur on. Solar aspects where old sun crusts exist are more prone to slide. Anticipate releases on slopes greater than 30 degrees and limit exposure  by traveling one at a time. Keep in mind that wind drifted snow, or wind slab could be significantly deeper and harder to anticipate (see wind slab problem above).

 

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Avalanche Activity

 

March 22nd – an impressive D3 natural slide in the Transitional Zone, on a steep unsupported S/SE aspect at about 4500ft. Occurred with direct solar radiation on the slope. This is an indication of the wide propagation potential and deep slab nature of our tricky persistent slab problem. South aspects should be considered highly suspect during times of solar radiation. Other aspects will likely also get into the action as temperatures warm up this spring.

Weather

Today the sun is coming out at times and temperature are increasing. Very cold overnight temperatures. Winds have calmed down today and blew strong from the North since Friday night to mid-day Saturday.  16-24″ of snowfall near town and closer to 4-8″ out toward the Canadian border fell across the mountains Friday.

 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*  24″ / 2.00*   0′  light, W  1″ /0.01*
Flower Mountain @ treeline  108  0″ / 0.00  5″ / 0.50*  0′  light, W  1″ /0.01*
Chilkat Pass @ 3,100ft  54.5″  0″ / 0.00  4″ / 0.30*  0′  light, W  1″ /0.01*

( *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 it 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

Slopes with wind slab and storm snow on solar aspects with old sun crusts are more prone to slide. Click the + Full Forecast link below for each zone to read more. Submit and read local observations below.