Here's a text link to a summary of current snowpack conditions throughout the West:
ftp://ftp.wcc.nrcs.usda.gov/data/snow/update/west.txt

Here are a couple snow sensors in the Yellowstone drainage inside the park:
http://www.nwrfc.noaa.gov/snow/snowplot.cgi?TOPW4
http://www.nwrfc.noaa.gov/snow/snowplot.cgi?NORM8

Current outlooks from NOAA are calling for a wet March. All of SW Montana and the park are under assorted advisories and warnings for heavy snow tomorrow and Monday. If you look at the graphs in the snow sensor links, you'll see that many of our sensors are already nearing their average peak snow depth for the year, with 6-9 weeks left to build more snowpack depending on elevation.

Bottom line: the snowpack is getting more and more above normal and you want to bear this in mind in trip planning. We expect great late summer conditions but a late end to runoff for the Yellowstone area, and everywhere else in MT (and WY as well) is in the same boat. It's still possible an early runoff could lead to near-normal conditions for summer, but I wouldn't count on it. We are not accepting float trip reservations before July 15 unless people are willing to switch it up in case the Yellowstone is still dirty.

Feel free to repost on other boards.