Haines Avalanche Center

Forecast Expired - 11/29/2020

Above 2,500ftHigh

1,500 to 2,500ftHigh

Below 1,500ftConsiderable

Degrees of Avalanche Danger

Avalanche Problems

Problem 1

Storm Snow:

Yesterday’s new snow (20+ inches) came in upside-down and weak underneath. All this new snow will need more time to settle and bond. Additionally, strong southeast winds have created wind slabs above treeline that will allow for wider propagation across a slope. Below the new snow, there are known weak interfaces within older storm layers (45-60cm deep) as well. Be careful to avoid terrain traps where small amounts of snow can pile up deeply. Slopes steeper than 30 degrees should be avoided. Steep openings in the trees will be likely places to trigger a slide.

(Click to enlarge graphic to read more…)

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Problem 2

Persistent Slab:

In areas above treeline, depth hoar exists at the ground. There are also 2 melt-freeze crusts just above this depth hoar and in the midpack. Any of these crusts can act as a bed surface and a weak interface within the old snow. Heavy new loading above these persistent layers has increased the likelihood of triggering these layers. This will be a problem on all aspects. Be especially cautious of steep, heavily wind-loaded areas above treeline, and unsupported slopes. Convexities, where there is a steep rollover, will be a likely place to trigger a deeper slab that runs to the ground with high consequences. This kind of danger is tricky and can be hard to manage, so a wide safety margin is recommended.

(Photo from Lutak Zone, 11/15, 2500ft, NE aspect)

 

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Avalanche Activity

Bad weather kept the mountains shrouded on Saturday. Please send in any observations of avalanche activity, including estimated depth, width, length, and location/elevation.

Weather

Saturday’s storm did not disappoint. About 24″ fell above 1,000ft in the Lutak and Transitional Zones. Southeast winds were strong throughout. Sunday should bring decreasing winds, light snow showers, and steady temperatures.

Monday night-Tuesday looks very wet, with multiple feet of new snow above the snowline, which should start at sea level and then rise quite high. Stay tuned! We have real concerns about Tuesday-Wednesday when a strong atmospheric river looks likely to hang over the area with rain reaching up to mountain top level towards the end.

 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
 69″ 24″ / 2.00 24″ / 2.00 1000 mod, SE 1″ / 0.10    *
Flower Mountain @ treeline
 44″ 24″ / 1.90 24″ / 1.90 1000 light, SE 1″ / 0.10    *
Chilkat Pass @ 3,100ft
 15″ 12″ / 1.00 12″ / 1.00 1000 light, SE 1″ / 0.10   *

( *star means meteorological estimate )

Additional Information

It’s time to start thinking avalanche. Dust off your gear and make sure it is fully functional. Put new batteries in your beacons! Do a beacon practice to start the season and keep your skills fresh. If you head into the hills, watch out for avalanche conditions, and be especially careful of rocks and hidden hazards like crevasses beneath the snow. WEAR A HELMET!

Education Video Links:

Announcements

We have begun periodic conditions updates for winter 2020/2021. Click the + Full Forecast link below for each zone to read more.