Triggered by another party, did not talk to them.

Snow involved took out the last 2 storms.

This area rolls a bit steeper than where the tracks to the skiers left are. tracks are after the fact, our party skied before we knew the slide had occurred, could not see from the entry from the ridge. 1st skier in our party skied past the debris, 2nd skier saw that the 1st was not involved. Remaining 3 skiers went after we conformed that no-one was caught. I double checked this with a stop and visual search from the crown and saw that no tracks were coming or going into the slide area.

Slide was heard by a solo skier approaching from porter fork. solo skier reported that one person may have been hit by the dust cloud (unconfirmed).

triggered remotely from approximately 150' away. - one can see the ski tracks looker's left of the crown -

tracks adjacent to slide on both sides were after the fact. no tracks entering the slide. Hopefully the responsible party will submit more information. triggered by a party skiing to the skiers right of the slide.

Occurred after many parties have skied in the area. Did not investigate the crown, too much hangfire. Stopped only long enough to ascertain that no one was caught.

We did an ECT test on the flank at about 1/3 height. No indications of instabilities. ECT was negative.

Note:

If this was not triggered by another party, it could have easily been triggered later in the day by my party. I began to initiate a rescue until I saw the 2nd skier in my party skiing next to the debris. He was able to determine that it was not triggred by the 1st skier without missing a turn.

We did not observe any signs of instability before the slide.

Forecaster (Hardesty) Comment: I went up to look at the slide today - the day after it was triggered. Found the weakness to be 1mm facets (picture below) above the Dec 4/5 rain event. Bed surface photo shows where in some places the upper rain crust stepped down 1-2cm on facets above yet another - 15mm - thick rain crust from Dec 2.

Much of Gobbler's into Porter Fork is thin - total snow depths averaged 3' deep and has well developed facet/crust sandwiches buried 1-2' deep on average. Crown depths ranged from 10" to just over 2' deep with slope angles (it rolls at the fracture line) to 40+.

Let's look at Ian McCammon's Lemons for structure within the snowpack.

• Concerning Weakness within 1m of snow surface - Check
• Persistent Weak Layer - Check
• Weak Layer Thickness less than 10cm - Check (roughly 2cm - see photo)
• Grain Size difference 1mm or greater - Check
• Hand Harness Difference Greater than 1 step: Check - facets (4F minus) overlying slab - varied from 1F to Pencil​

Now for the $69 dollar question - Why there? - particularly with all the tracks nearby? Good question indeed. Here are a couple thoughts.

1. The Solstice wind event (strong south/southwest winds) resulted in odd loading patterns...perhaps the slab (1F-Pencil) was more pronounced mid-slope.
2. The facet/crust sandwich is more of a troublemaker at this elevation (9500') rather than much higher...rain is elevation dependent.
3. Most of the tracks looker's right came after the the event...and perhaps could have well triggered it themselves had it not previously been remoted.