Danger Rose Tutorial

Once you learn how to read it, the danger rose is a quick, powerful way to visualize avalanche danger by aspect and elevation.

Here is a cool graphic by ex-Utah Avalanche Center forecaster, Andrew McLean:

In the graphic below, imagine looking down on a cone-shaped mountain.  The center of the circle is the top of the mountain and the outside of the circle is the bottom of the mountain.

We can "paint" the danger onto the landscape, looking here from the top of Little Cottonwood Canyon. Notice that since north is to the right in the photo, you have to rotate the circle 90 degrees to the right in your mind.

Remember that this tool only helps you to visualize the GENERAL avalanche danger patters by aspect and elevation only.  Be sure to read the text for the details. In the real world, avalanche patterns are more complex than a danger rose. Also, in the photo above as an example, south facing slopes have many terrain features, such as a gully, which has terrain that may face east or west.  An east facing slope is an east facing slope, whether it's a 10-foot side of a gully or a large avalanche path.  Finally, If we use the rose to indicate wind slabs at upper elevations, often those same wind slabs can occur on lower elevation spur ridges that jut out away from the protection of the larger mountains.  It's impossible to show these on a danger rose, but we often describe those conditions in the text.

 What are "Pockets of the Next Higher Danger Rating"?

Sometimes avalanche danger is what we call "pockety" meaning that you can find localized, areas where the danger rating is one notch higher.  We represent these using the little circles.  For instance, wind slabs are often pockety in nature. Also, the more time that has passed since the last storm, the more the snowpack becomes "spatially variable" as we call it, in other words, pockety.  Sometimes these pockets are easy to recognize and avoid, such as with wind slabs, because they are right on the surface and anyone who knows how to recognize the smooth, rounded shape of a wind slab can easily avoid them.  At other times, such as with persistent slabs or deep slabs, these pockets are completely invisible unless you are willing to dig a lot of snow pits.  In these cases, avoidance is often the best option.

How to Manage Terrain based on Danger Ratings

An easy way too choose appropriate terrain based on danger ratings is to adjust the slope steepness; the more dangerous the terrain, the gentler the slopes you choose.  Remember that especially at higher danger ratings, you have to consider the terrain the slope is attached to, especially the terrain above the slope you plan to cross.  In hazardous conditions, you can easily trigger slopes from the bottom, the side and even from flat ridges above the slope.

Courtesy of the Swiss Institute for Snow and Avalanche Research