Center for Snow and Avalanche Studies

Swamp Angel Study Site
Swamp Angel Study Plot (subalpine)

Senator Beck Study Site
Senator Beck Study Plot (alpine)

Putney Study Site
Putney Study Plot (summit)

Senator Beck Basin Stream Gauge
Basin Stream Gauge

St Paul Basestation
St. Paul RF Base Station

The Center for Snow & Avalanche Studies serves the mountain science community and regional resource managers by hosting & conducting interdisciplinary research and conducting integrative 24/7/365 monitoring that captures weather, snowpack, radiation, soils, plant community and hydrologic signals of regional climate trends.

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Mountain System Monitoring: Winter Storm Data

  Past Winter Storm Reports:

This CSAS Storm and Precip Data xlsx file contains the current and past 11 seasons of CSAS winter storm data, including:

  • Dates, times and duration of each winter storm event
  • Change in the height of snow at both our alpine Senator Beck study plot and our subalpine Swamp Angel site.
  • Peak gust data from our Putney site.
  • Mean and maximum precipitation intensity during each storm
  • Total new water accumulation in mm for each storm event.
  • Summary data for each month of the season.
  • Cumulative annual precipitation graph by month

See our Current Conditions for the latest hourly data. All times shown are in Mountain Standard Time (MST)

2014-2015 Winter Storm Reports:

Storm #11 at Senator Beck Basin
Good morning from Silverton -

Our long, dry March finally produced another (minimal) winter storm here at Senator Beck Basin.  Since Storm #10, ending on Monday, March 2, we had received only 6 mm of precipitation (March 18-19) before a short burst of snow yesterday, Wednesday, March 25.  This Storm #11, however, barely met our criteria with just 12 mm of water content.  Winds were NW'ly and no desert dust accompanied this weather event at Senator Beck Basin.

Given the current weather forecast it appears highly unlikely that we will experience another winter storm in March, ending the month with only 11 storms to-date, since October 1.  As of the end of March last winter (2013/2014) we had logged 19 storms, and at the end of March in the very dry winter of 2012/2013 (Water Year 2013) we had logged 18 storms.  Fortunately, offsetting this low storm count, this winter, we have had several significant storms and we may end March 2015 with 545-550 mm (almost 22") of total precipitation for WY 2015,  versus only 489 mm (19.3") total from the 18 storms of WY 2013.

We have plotted cumulative monthly and daily precip totals at our Graphed Data - Precip webpage - those will be updated on April 1.

Attached is a detailed Storm #11 Report.

More soon,

Winter Storm #10: February 28 - March 2, 2015
Greetings on Tuesday morning, March 3, as the sun emerges here in Silverton. 

Even though we may see some bursts of light snow later today, we have recorded a 12+ hour lull in measured precipitation since 2100 hrs yesterday evening, at the Swamp Angel Study Plot.  That lull triggers our rule (no break in precip of 12 hours or more) and signals the end of our Storm #10 event, which was quite windy and delivered 2.4" of snow water equivalence to our Senator Beck Basin.  A complete Storm Report is attached.

More soon,

Winter Storm #9: February 25-26, 2015
Good morning on Friday morning, February 27,

On Wednesday evening, Feb 25, we received a small storm on N'ly flow at Senator Beck Basin that spilled over into Thursday morning.  This storm just barely met our precipitation criteria, at 12 mm of water content.  A complete Storm Report is attached.

Now, of course, we're anticipating the second major winter storm within a week, beginning this afternoon.  This long duration weather event may run into Tuesday or Wednesday, perhaps with enough of a break (i.e., 12 hours without measured precip) in the early week to document as two separate winter storms.  In any case, the next several days have the makings of "an experience" for us here in Silverton ... described yesterday by NWS as "ground zero" for this storm!

More soon,

Winter Storm #8: February 22-23, 2015
Good Tuesday morning, February 24, from Silverton -

Clearing skies last night signaled the end of Winter Storm #8 that began early Sunday morning.  Silverton was awash in 18-20" of new snow by Monday evening and Senator Beck Basin saw gains of over two feet in snow depth.  This storm was notably un-windy and enabled our alpine Senator Beck Study Plot to finally accumulate some considerable new snow without seeing it immediately blow away.  In the end, this storm delivered a little more than 2" of water equivalent, a nice start to what we will hope is a wetter period to come with storm upon storm.  At 8 storms to-date this winter, we are 7 storms behind the storm count on this date last winter, and 7.5 behind our 2004-2014 average count by the end of February of 15.5 winter storms.

A complete Storm #8 Report is attached.

More soon,

Winter Storm #7: February 15-16, 2015
Greetings from Silverton -
Finally, starting last Sunday afternoon and ending Monday evening, Senator Beck Basin received another, albeit minimal, winter storm, our first in over a month.  Although we gained 7" in snowcover depth at the subalpine Swamp Angel Study Plot, sustained N'ly and NW'ly storm winds allowed only a 3.5" gain at the alpine Senator Beck Study Plot during the storm, and that was short-lived.

The complete report for Storm #7, WY 2015 is attached as a PDF.

More soon,

Winter Storm #6: January 12-13, 2015
Greetings from Silverton -
The western San Juan Mountains just received a gentle and small storm, just meeting our storm criteria of 12 mm of water equivalence. The Storm Report #6 report is attached. This small storm was preceded by another small batch of snow containing 8 mm of water on Sunday, January 11th, with an 18 hours gap in precipitation before Storm #6 began.

Storm #6 was notably un-windy, particularly in comparison to the preceding Storm #5. As the storm cleared yesterday evening, the peaks around Silverton were beautifully 'sugar-coated' with new powder snow ... Storm Report #6 (pdf).

We'll hope for another, larger storm soon,

Winter Storm #5: December 21 - 23, 2014
Here is a final Storm Report for Storm Report #5 here at Senator Beck Basin and Red Mountain Pass.  With 2.3" of water equivalent, and an average wind speed of 37 mph for the 53 hours of storm duration, Storm #5 was nothing less than a 'major disturbance' to our snowcover.  

Of perhaps most dramatic impact was the spectacular erosion of snowcover at our alpine Senator Beck Study Plot, located in the upper basin at 12,180'. There, after briefly gaining a few inches of snow depth early in the storm, the ferocious winds actually stripped almost 24" of the new and older snowcover away leaving only 5" of old snow on the ground under our ultrasonic snow depth sensor.  Some fraction of that eroded snow was sublimated by those winds, but a great deal of that eroded snow volume was redeposited on leeward slopes downwind.  Storm Report #5 (pdf).

After a brief lull today we're looking forward to another Winter Storm for Christmas ...

Happy Holidays,

Winter Storm #4: December 13-14, 2014
Greetings from Silverton on Monday morning, December 15 - It's a clear, 'crisp', San Juan morning, at -6 F here in town, with bright sun on the peaks above.

Aside from receiving 11 mm of precip on December 3rd (just 1 mm short of our threshold for a Winter Storm), our dry-ish December ended last weekend with a slightly over-achieving Storm #4 producing a 37 cm (14.6") gain in snowpack depth and a 32 mm (1.26") gain in snowcover water content.  The Storm #4 Report is attached.

We'll hope that the Pacific keeps sending systems our way.  California may have a love/hate relationship with these major "atmospheric river" precipitation events, aka "Pineapple Express" storms, but Colorado probably can't get enough of them, even if we're just getting the dregs. Storm Report #4 (pdf).

Winter Storm #3: November 22-25, 2014
Greetings from Silverton - It's a very mild (28 F) Wednesday morning, November 26, a nice reprieve from a string of cold mornings.

Here is the Storm Report for our third winter storm of winter 2014/2015. This storm began with some intensity for the first 24 hours but then tapered to a long-duration, lower intensity event. One long interval of 10 hours without a recorded mm of precip almost ended the storm at 2000 hrs on Monday (using our 12-hour break in precip rule for 'storm end'). That would have shortened the storm length by a full day but another 4 mm fell on Monday and stretched the storm to 2000 hrs Tuesday, for a full 72 hours in duration.

Storm #3 was a significant precip event with quite sustained NW-N winds. Wind redistribution of the 1.8" of water equivalent resulted in substantial loading to leeward slopes (and cross-loading of terrain on some windward slopes). And, winds continue this morning, still from the NW. But, given the sustained storm period winds, there may not be much loose snow left in the fetches to move.

This Storm #3 has brought our Water Year (Water Years start October 1) total precip to 197 mm, a little shy of the 210 mm we had received in October and November 2013, last winter, after a total of five winter storms. Our 11 year period of record at Swamp Angel Study Plot has averaged 1.8 numbered winter storms in October and another 3.1 storms in November, with an average total of 191.5 mm of precip collected by the end of November. So, we're a little short on numbered storms so far this year, but a little above that average end-of-November total precip. Storm Report #3 (pdf).

Winter Storm #2: November 14-15, 2014
Greetings from Silverton - Sunday morning dawned clear and cold (5 F in Silverton, -4 F at Putney) here in the western San Juans following a long winter storm - our Storm #2 of the winter of 2014/2015. Storm Report #2 (pdf)

The prior, 'tentative' Storm #1 earlier this month did, in fact, linger just long enough with snowcover over more than half of Senator Beck Basin, albeit very thin cover, to 'count' as #1 . We will find that Storm #1 layer in our snow profiles for the rest of the winter, at least at the higher elevation Senator Beck Study Plot. Now we're really in business with a half-meter of snowcover and more over the entire Basin.

A special thanks to the many of you who have made your Winter 2014/2015 Friends of the CSAS contribution ... kudos to you! For those who would also like to contribute, and sustain our data collection at Senator Beck Basin, see: You can donate through PayPal or simply send a check to CSAS at the address shown.

Winter Storm #1: November 2-3, 2014
After a dry October, with only a couple of very minor and short-lived snowfalls that quickly melted back to the ground, we finally received a snowfall last weekend that may comprise the basal snowcover in Senator Beck Basin for this winter. We'll see - we're in for a sunny period ahead and we may lose this snowcover too. But, so far, the new snow is hanging in there over the majority of Senator Beck Basin and at our two study plots. So, tentatively, I'll consider this event as Storm #1 at Senator Beck Basin for winter 2014/2015. Storm Report #1 (pdf)