Trip Report    

Alpine Scramble - Pratt Mountain/Mason Lake Shuttle Trip

Pratt Mtn is an old fav, but this time we dressed it up by dropping off the top via the west ridge and finding our way out via Rainbow and Mason lakes. A classic Andy Cahn adventure.

  • Road suitable for all vehicles
  • We dropped a car at Exit 42 and drove up to the usual Pratt/Granite Mtn trailhead at Exit 47. The elevation at the trailhead is about 1900 ft. There was little or no snow on the trail until we got to about 3500 ft. Thereafter there was hard pack and fresh slush on the trail. As we got up just past Olallie Lake there was 4-12 inches of fresh snow. We went up the SE ridge, and put on our snowshoes pretty quickly after climbing above the lake. The snow conditions made for relatively easy climbing, although we did have to break trail the whole way. When we got to the rock ridge section that is a few hundred feet below the summit, we traversed around to the right. We got out helmets and ice axes here, but the traverse was straight forward.  The forecast gave us hope for some sun breaks, but we were fogged in for most of the day.  So no big views, but also no wind! 


    We didn't have a known route for going down the backside, so it was make it up as you go. We dropped down the ridge to the west for 150 ft or so and then had to find our way down another 600 ft before getting to the flats approaching Rainbow Lake. We made our way down a long snow field. Some of us opted to keep our snowshoes on. Others chose to plunge step. This is the one section that could be tricky depending on conditions. The area lights up under slope angle shading. For us, the snow conditions did not present a hazard, but if it was icy or a risky avy day, this section would require some careful consideration or a search for an alternative way down. It is not clear what is under the snow for a summer trip, but I think it is reason to expect that you could find a way down. 

    The trip out once we got to Rainbow Lake actually took more attention than we anticipated. There is a trail through there, but it was of course buried by lots of snow.  So the name of the game was group participatory route finding. Although the way up to Pratt Mtn is understood and and straight forward, most of the way down and out was a classic find-your-way scramble. What could be better than that. 


The final ridge run up to the summit.


Cornices to the right just after we came off the peak. Group decision - go left!


The long snow field heading down the Rainbow Lake.