An Independent School • Grades 5-12

by Vishnu I. '22

The Northwest Avalanche Center (NWAC) is a nonprofit that posts daily avalanche forecasts during their operational seasons (October to May) with the goal of equipping their backcountry users with mountain weather, education, and data to increase safety. Each daily post contains a forecast for the next day and an outlook for the day after that. These posts utilize a five-level danger rating system: low, moderate, considerable, high, extreme. For example, on Wednesday, they may state that near the treeline, Stevens Pass has a danger rating of ‘Low’ on Thursday and ‘Moderate’ on Friday. However, due to limited funding and the demands of a daily operation cycle, NWAC is focused on producing daily forecasts rather than retrospective analysis on past data. My project is centered around analyzing trends from NWAC’s past forecasts in hopes of making future forecasting more consistent. 

I first enhanced a program that previously read NWAC’s 2018-19 forecasting data and enabled it to read this season’s data. After some debugging and accounting for differently formatted data, I produced many bar graphs that detail the danger ratings for different locations and elevations. One such graph is displayed below, which shows the individual danger ratings for elevations above the treeline at Stevens Pass for this year’s avalanche season. The blue bars show the ratings for day one forecasts, and the grey bars show day two forecasts. From this graph, we can conclude that for the considerable danger rating category, the difference between the number of Day 2 forecasts and the number of Day 1 forecasts is very high; in fact, this difference has increased over the past three years (older data not shown here). These findings suggest that the consistency of future forecasting can be improved. Take a look at Colton’s blog to find out more about specific shifts in Day 1 and Day 2 forecasts.

Figure 1: Shows day one and day two frequency distributions for danger ratings above the treeline at Stevens Pass for the 2019-2020 avalanche season.

In addition, I created another program that outputted this season’s data as a comma-separated values (csv) file, which was a more granular way of representing the data. This csv file is available to further assist the NWAC forecasters in their computations. Finally, I analyzed some trends in the data. Shown below is a graph that displays the mean danger ratings for all the regions and elevations for day one forecasts. A mean danger rating of 1.0, 2.0, and 3.0 represents a ‘Low’, ‘Moderate’, and ‘Considerable’ forecast respectively. Some conclusions that can be made are that the Cascade West North region (CWN) has the highest danger rating for Day 1 forecasts. In the future, my ultimate goal would be to compare other parameters determined in forecasting with each other, which will hopefully make forecasting even more consistent.  

Figure 2: Shows the mean danger ratings for day one forecasts by region and elevation for the 2019-2020 avalanche season.

 Figure 3: Shows a visual map of all the regions NWAC takes data from.