Hatcher Pass Avalanche Center

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ARCHIVED - Forecasts expire after 24 hours.
Issued
Sat, February 16th, 2019 - 7:00AM
Expires
Sun, February 17th, 2019 - 7:00AM
Forecaster
HPAC Staff
Avalanche risk The Bottom Line

A weather pattern change is expected today through Monday. Significant new snow is expected beginning tonight through Sunday which will increase the avalanche hazard to CONSIDERABLE tonight. Preliminary estimates could put snow totals from today through Sunday at 14-20″.

Today, a MODERATE avalanche hazard exists for stubborn to unreactive persistent slab avalanches at mid to upper elevations, on a variety of aspects, 0.5-3 feet deep, on slopes 35° and steeper, and may be large enough to bury, injure or kill. Human triggered avalanches are possible and natural avalanches are unlikely.

This kind of avalanche problem is difficult to assess and may behave unpredictably.

Today, a LOW hazard exists at low elevation.

For today, safer, good riding conditions can be found in wind protected areas at the lower elevations. Other areas include wind protected, low angle slopes, at the mid to upper elevations, out of the runnout of steeper slopes from above.

Sat, February 16th, 2019
Upper Elevation
Above 3,500'
2 - Moderate
Avalanche risk
Mid Elevation
2,500'-3,500'
2 - Moderate
Avalanche risk
Low Elevation
Below 2,500'
1 - Low
Avalanche risk
0 - No Rating
1 - Low
2 - Moderate
3 - Considerable
4 - High
5 - Extreme
Avalanche risk Avalanche risk Avalanche risk Avalanche risk Avalanche risk
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.
Recent Avalanches

Yesterday a human triggered avalanche was triggered on the Truck Ramp, North side of Pinnacle Peak, in the Archangel Valley. This avalanche occurred on old, stiff, pillowed, wind deposited snow, sitting on facets over the (2/5) Chinese New Year’s Crust. It was very stubborn to trigger. Debris was shallow and not likely to bury a person, but the avalanche size was big enough to injure a person if they were caught and washed. One person was caught, but arrested within 15 feet. No injuries.

Truck Ramp, SE, 5300′, SS-ASc-D1.5-2-O,  intentionally triggered at indicated trigger point in picture 40-50′ wide, 4-8″ deep, propagated around the corner and into the couloir on right, pulling out another starting zone and crown zippering down the sidewall of the couloir, 20′ wide, 2-8″ deep. Crown was continuous, one avalanche, two paths. Ran 800-900′ long.

Weather
Sat, February 16th, 2019

This week’s weather at 3550′:

Temps averaged 17ºF, with a low of 2ºF and a high of 32ºF.

2″ of new snow accumulated this week with 0.16″ SWE.

Overnight at 3550′:

Temps averaged 17°F.

No new snow.

This week’s weather at 4500′:

Temps averaged 13ºF, with a low of 1ºF and a high of 30ºF.

Winds averaged ESE 4 mph, max 13 mph . Gusts averaged 10 mph, max gust SSW 27 mph.

Overnight at 4500′:

Temps averaged 18ºF overnight, with a Low of  16ºF.

Winds averaged E 4 mph overnight. Max gust S 14 mph.


NWS Rec Forecast HERE


NWS point forecast HERE


State Parks Snow Report and Motorized Access information HERE


TREND – Rising avalanche hazard tonight through Monday.

A change in the weather pattern will begin today, with good chances for snow accumulation at HP through Monday. More chances for snow exist through the week with several low pressure weather systems in the line-up for south central AK.

2″ of new snow (0.14″ SWE) and light winds are forecasted today. This will not increase the avalanche hazard rating today. However, if the timing of the incoming storm is forecasted incorrectly and we get more than 6-8″ of snow today expect the avalanche hazard to rise abruptly.

NWS is forecasting 5-8″ of new snow tonight. This will begin to tip the balance and allow for some possible natural avalanche activity to begin.

Moving into Sunday a significant weather system could push snow totals from Saturday into Sunday evening close to the 20″ mark. Expect the avalanche hazard to rise to CONSIDERABLE at mid to upper elevations tomorrow, and MODERATE at low elevations. Weak layers in the snowpack have been re-activated by similar loading cycles this season, and tomorrow is no exception.

Monday is a bit far out for weather forecasting accuracy, with some model discrepancy, however, there is a chance for upper level SW flow, and another classic Hatcher Pass Dump. If this occurs more natural avalanche activity will be on tap.


This morning’s NWS point forecast for Hatcher Pass:

Today
Snow, mainly after noon. High near 18. East wind 5 to 10 mph. Chance of precipitation is 80%. Total daytime snow accumulation of 1 to 2 inches possible.
Tonight
Snow. Low around 18. East wind 10 to 15 mph. Chance of precipitation is 80%. New snow accumulation of 4 to 6 inches possible.
Sunday
Snow. The snow could be heavy at times. High near 25. Southeast wind 15 to 20 mph. Chance of precipitation is 100%. New snow accumulation of 9 to 13 inches possible.
Observations
Recent Observations for Hatcher Pass