CalTopo - See crevasses on the new MapBuilder Topo layer
If you’re new to CalTopo and want to learn the basics, get started with this video. (Disclaimer, it's mine.)
Sidenote: CalTopo offers a lot of free mapping resources, but I recommend you support their fine work and get even more goodies with a modest annual subscription.
CalTopo, my favorite backcountry mapping software, recently added a cool new feature to their default MapBuilder Topo map layer that can be helpful for alpine trip planning: LiDAR elevation model data.
(For the folks who appreciate spelled out acronyms, LiDAR stands for “Light Detecting And Ranging”.) High resolution LiDAR imagery can create extremely detailed and accurate elevation models of the earth.
Why is this cool? You can see crevasses! Check out the examples below of Mt. Baker in the Washington Cascades.
The first image is a previous iteration of MapBuilder Topo. Certainly a nice enough map, but no indication of where crevasses might be. (The purple line is the popular Coleman-Deming Glacier climbing route.)
Now, let's have a look at the same area and map layer, but with LIDAR digital elevation data added. WHOA! Check out those crevasses! Can you see why the the Coleman-Deming route goes where it does? It misses most of the big ones.
The crevasses are even more impressive zoom in a bit more. Here's some detail from the upper part of the route.
Now, this added LiDAR imagery comes with a BIG disclaimer. As every alpine climber hopefully knows, crevasses can change on almost a daily basis. The image represented on this map layer is a one time snapshot, and you should be not rely on it for fool-proof crevasse avoidance.
On the other hand, crevasses often tend to form in pretty much the same place year after year, so imagery like this can be helpful for general purpose route planning.
Keep in mind the old cartographers saying, “the map is not the territory”. Meaning, pay attention to what's really on the ground in front of you, not your GPS screen, track, or high-tech imagery like this.
