Welcome to Snowpack Tracker for the winter yurts operated by Wilderness River Outfitters (WRO).

This web application provides visualization of weather data for the Lost Trail Pass area, with avalanche hazard ratings for the Bitterroot forecast area sourced from the West Central Montana Avalanche Center (WCMAC). All data is updated hourly.

Data View Options

Season Tracker

Displays data at 24-hr resolution, intended as a tool to track seasonal trends in weather and avalanche hazard. The date range slider can be used to view any time range within the current season, while the drop-down menu will switch to an Oct. 1 - June 1 view for historical seasons. Default page load is for the previous 30 days. To return to this view, select "Current View" from the drop-down. Data plotted for the current day represents derived variables calculated using partial-day observations up to the most recent hour.

Precipitation is displayed as 24-hr accumulated snow water equivalent (SWE), derived from hourly SNOTEL snow pillow data.

Wind direction is plotted as a rotating vector, where the vector indicates compass direction that wind is from. Wind direction vectors are best viewed for time ranges of 3 months or less.

Forecast avalanche hazard ratings use the North American Avalanche Danger Scale, with the following color code:

• Grey: No hazard rating issued
• Green: Low hazard
• Yellow: Moderate hazard
• Orange: Considerable hazard
• Red: High hazard
• Black: Extreme hazard

Note that the WCMAC does not provide a forecast for the Bitterroot forecast zone on every day.

Storm Tracker

Displays hourly weather station data for the previous 14 days. If sub-hourly data is available, wind speed is the average and max for previous hour, and precipitation is the sum for previous hour.

Precipitation data at SNOTEL sites is derived from hourly precipitation gauge data (not snow pillows).

Wind direction arrows indicate the direction the wind is blowing, best viewed at time ranges of 1 week or less.

Data Sources

Weather data is sourced from the Synoptic Data API, reported at hourly intervals for all stations.

Weather stations include:

• Saddle Mtn (SDMM8) (SNOTEL)
• Moose Cr (MOKI1) (SNOTEL)
• Lost Trail Pass (ITD87) (ITD)
• Kriley Cr (BKRCI1) (BLM RAWS)
• Hells Half Acre Mtn (HHAI1) (BLM RAWS)

FAQs

Where can I get the raw data?

Visit Synoptic Data to learn more about the Mesonet API services, which provide access to surface weather data across North America and globally. For more information on avalanche events and hazard data, contact the West Central Montana Avalanche Center (WCMAC).

Can a version of this web application be designed for my forecast center or highway avalanche control operation?

Yes! We have intentionally designed Snowpack Tracker to be transferable to additional regions by leveraging generalized templates and standardized weather data from the Synoptic API. Contact Patrick Wright (pwright@inversionlabs.com) or Tobey Carman (tcarman@inversionlabs.com) for additional information. Visit us at inversionlabs.com.

What software tools do you use?

This web application is written primarily in Python, using Pandas, Bokeh and Flask. Huge thanks to the core developers and open-source community that support these tools!