last updated at Mon Feb 01 2016 04:10:25 GMT-0500 (EST)
Recent traces are bright yellow; older traces fade to dark red. Colors are per-hour, until the darkest layer which contains everything from 9 hours ago to the end of the storm. (fullscreen)
Please keep in mind that GPS data is lossy, as is the map-matching process used to snap traces to road geometry.
Code available under an ISC license. Please consider all contents of this page to be CC0 (well, okay, except the Simpsons video).
I'm Tom Lee and I work at Mapbox, purveyors of fine open-source geospatial technology. You can even use it for applications unrelated to snow!
Feel free to get in touch -- @tjl on Twitter or thomas.j.lee at Google's popular email service.
Many thanks to the DC government for tolerating my scripts. I would love to talk to you cats about the miracle of JSON.