The peak backpacking season is almost here, and many backpackers with planned trips in the Mountain West are asking the same question: “What is the current state of the snowpack?” This is especially the case in areas that had wet winters and springs, notably the High Sierra, Colorado, and Wyoming.

Historically, I’ve relied on SNOTEL sensor data, the National Snow Analyses, and recent trip/route information (via social posts, online trip reports, and rangers). But CalTopo just added a new imagery layer that is perhaps more useful than any of these.

Its new Sentinel high-res satellite data will be updated weekly, and paints a very clear picture of the current snowpack. For example, below is the snowpack on July 1 around Rock Island Lake, which is one of my favorite spots in northern Yosemite and which I’m hoping to visit during my guided trips there later this month. It’s still thoroughly snowbound, but Slide Canyon is melted out, and the snowline will continue to climb.

This is a great resource, and I hope that backpackers utilize its potential.