Information from Utah County SAR:
"What I do know is that there was a 41 y.o. male, his brother, and his 15 y.o. son that left the Dry Canyon trailhead approx. 1 a.m. Fri. to attempt a summit bid of Timp via the Everest Ridge. The group appeared fit, prepared (proper clothing, mountaineering boots, crampons, ice axes, but did not have beacons and avalanche gear) and was at least somewhat experienced with mountaineering and snow climbing. Somewhere around 10,000' +/- on the ridge they turned back as there were very strong winds. On the way down the 41 y.o. male victim was glissading and triggered a shallow wind slab that carried him over a couple of small cliff bands and some distance down the mountain. He was fully buried, but shallow enough to dig at least his torso out and full escape the debris with the assistance of his brother and son. The other 2 climbers were not caught in the slide. The victim, who was wearing a helmet did hit his head, had no apparent head injuries, but had an obvious lower leg fracture. His brother and son assisted him down the gully east of the ridge to an elevation approximately even with the Baldy Saddle (8,500'). The Everest Ridge has a SSW aspect, but it is unclear to me if they were on the ridge itself or to the east when the avalanche occurred. The brother of the victim then went down the mountain to get help. Our team was dispatched around 9:30 a.m. and were shuttled to the saddle by LifeFlight, treated the victim, moved him approximately 1/4 mi. to the helicopter and he was transported to Ut Valley hospital by LifeFlight."
"A wind slab appears to have been instrumental in a mountaineer getting carried over a few small cliff bands while glissading. He was buried shallowly enough that he was able to get himself partly out, then the rest of the way with help from his climbing party, who did a great job until SAR and Life Flight arrived to bring him the rest of the way down the mountain. I strongly suspect that he wouldn't have been injured if he wasn't glissading with crampons on. PLEASE DO NOT GLISSADE WITH CRAMPONS ON! Many people have told me that they simply keep their heels up and are perfectly safe, but I've also carried multiple people off the mountain who snap their tib/fibs when the crampons catch for a variety of reasons. (Micro spikes are probably fine.)"
Forecaster note: A wind slab is probably a good guess. This also sounds like an example of where even a small slide can have serious consequences in more radical terrain - where you could go off cliffs or into trees. Basic avalanche gear - a beacon, shovel and probe - should be carried by each person recreating in avalanche terrain - snow covered mountains.
The party did a great job in completing the rescue, getting the injured person to a good spot and then going for help.
Elevation (10,000') and aspect (south or southwest) are estimates.
Map below from Summit Post web site, showing Everest Ridge on Mt Timpanogos.
Of note is the northwesterly winds on an 11,000' peak to the north of Mt. Timpanogos picked up around 1 am Friday morning, averaging to 55 to 60 mph, with gusts in the 70s and 80s for about 6 hours.