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Avalanche Cycle – January 17, 2016

20160117 Tuckerman Bowl

The Center Bowl and Lip area of Tuckerman. Snowfields are growing here and beginning to be active slide paths.

Helon and I got up into Tuckerman early this morning and were treated to the sight of two fresh piles of avalanche debris and one older pile. With our avalanche eyeballs wide open, we welcome the arrival of the 2015-2016 avalanche season. The recent slides were likely from overnight or early this morning, as they were both very soft and had slightly different levels of wind effects on the debris. The older slide was probably from earlier this week.

20160117 Chute

Looking up into the Chute variation, the narrows of the Chute is out of sight on the right. The crown was probably a couple feet deep or more in the center of this photo.

The first of the recent pair came from the Chute. We believe all the debris came from the crown lines visible in the picture, across the narrows of the gully, into the variation to the lookers’ left of the main path, and down along the buttress. Debris from this was approximately 2′ deep, some less, some more. The crown ranged in size from a few inches deep to a few feet deep.

20160117 Left side of Tuckerman

Two debris piles are visible, one above Helon and the other above and right of him. Crown lines are in the narrow sections of the Chute and far left side of the headwall.

The second of the pair was from the far left side of the Center Bowl, just to the lookers’ right of the Chute. The crown was still visible beneath the ice bulge, although wind loading was ongoing and working to fill it in. This slide was a little smaller than the Chute, with debris being about 12-18″ deep and a max crown depth of 18″ (just a guess, as we couldn’t access the deepest location and it had been partially reloaded.)

Even though we hadn’t yet begun using the 5-scale danger rating system, these new slides were not completely unexpected. We were a little surprised at the size; I’d call them both D1.5R1, but they are at the larger end of the R1 size. The one that surprised me a little is the older slide that crossed the hiking trail down low in the flats. The trajectory of this shows it coming from the Center Bowl and left side of the Center. Based on how far it ran in lean conditions and weather history, it was likely a pretty hard slab.

20160117 Debris in floor of Tuckerman

Avalanche debris in the floor of Tuckerman. The hiking trail is on the left side of this picture, under the debris. The extent of the tracks on this pile tell us that the slide happened before this weekend.

Here's clear evidence of an avalanche. These trees are flattened by the debris near the toe of the runout.

Here’s clear evidence of an avalanche. These trees are flattened by the debris near the toe of the runout.

After returning down to Hermit Lake, we got a report of another small avalanche triggered by a skier. This was in the area we call “Chicken Rock Gully,” which is the small terrain feature that fills in between the Open Book and Lunch Rocks, and from the top you can go right into the Sluice or Left into the Lip. The party triggered the slide near the rocks at the top of this slope. They reported that it was about 4-6″ deep, 40′ wide x 50′ long, and ran down to the bottom of Lunch Rocks.

Jeff Lane, Snow Ranger
Mount Washington Avalanche Center