Mt. Alyeska Avalanche
From "The Snowy Torrents"

April 12, 1969, 1 chairlift damaged.  Weather Conditions: The weather during early April in the Mt. Alyeska region of Alaska had been very unsettled with intermittent rain and snow.  Total new snow at the midway station (elevation 1,400 feet) at Mt. Alyeska Ski Area was 26 inches for the period from April 6 to 12.  Temperatures at midway remained almost constant during the period, ranging from 30 to 33F.  Precipitation fell as rain from sea level to 500 feet, mixed rain and snow from 500 to 1,500 feet, and snow above 1,500 feet. Therefore, snow amounts were much higher in the starting zones of the avalanches that threatened the ski area than in the midway study plot.  Wind action on the new snow was visible on the upper areas when the weather permitted observation.  Snow conditions on the upper mountain were becoming increasingly more unstable, but poor visibility prevented the upper gun from being fired at these targets.

Accident Summary: On the morning of April 11, the lower 75-mm recoilless rifle was blind-fired at Max's Mountain because low clouds obscured the mountain.  Eight rounds failed to release any snow.  The upper gun again was not fired because it was not set up for blind firing.  Rain and snow continued until the morning of Saturday, April 12, at which time the skies cleared.

On Saturday morning both the lodge and the ski patrol buildings were cleared of people before firing began.  The lower gun released a large hard-slab avalanche on Max's Mountain.  It ran fast and dry until it reached the heavy, wet snow at the 1,500-foot elevation; from there it continued as a wet-snow avalanche, digging to the ground.  It moved very slowly near the end, finally grinding to a halt 300 feet above No. 3 rope tow.

At 09:00, Snow Ranger Chuck O'Leary and his gun crew secured the lower gun and rode the chairlift to the upper 75-mm rifle.  The first shot was on Center Ridge and released a large hard-slab avalanche which ran across the Main Bowl trail.  Seven more rounds were fired into the Main Bowl area, releasing two more avalanches in the Shadows.  It was now 10:30, and the skiers were getting restless.  It was decided that although the lift line and Racing Trail areas would be opened for skiing, the Bowl and the trails immediately below it would be kept closed.  The Saddle and Shadows on the back side of Max's Mountain would be shot at the end of the day.

Hand charging and test skiing released only one small slide in the rest of the ski area.  Many of the skiers fell down repeatedly trying to ski the heavy, wet snow but no problems developed.  When the lifts closed at 16:30, O'Leary and three others went to the upper gun and prepared for shooting.  At 17:10 when the all-clear was given by radio from the base area, firing began.  Several rounds produced one small slide in the Shadows area.

The gun was then turned to the Saddle where the first two shots failed to release anything.  The third shot was put into the upper left side. A large fracture line shot across the top of the Saddle for a distance of 600 feet, setting a major avalanche into motion.  It moved very fast down the steep wall, throwing up an enormous dust cloud.  The gun crew radioed to the bottom alerting them that a large avalanche had started.

As the avalanche moved across the lower part of Silvertip, the dust cloud began to diminish.  The moving snow was now out of sight of the gun crew.  The lower radio then called and stated that they had seen the dust cloud settle and everything appeared to be all right.  The gun was then turned to the next target, and two more rounds were fired with negative re