Winter Storm #23, April 13-14, 2019:

Despite the fact it appears as though Spring has sprung with advent of daylight savings, Storm 21 (in addition to some more precipitation forecasted for later this week) continues to remind us in the San Juans that winter is not yet over.

Please see Storm 21 attached.

More to come soon!

Storm #16 hit the San Juans on Sunday afternoon. With peak precipitation rate at 1 mm/hr, the snow trickled in slow and steady over a three day period accumulating in 0.7 inches of water by Tuesday night. Several moisture surges and shortwave troughs released the precipitation with wind averaging between 10 and 20 mph; considerably calmer conditions than Storm 15. Peak gust from Storm 16 was 50.8 mph.

Storm 16 concluded with a winter advisory watch for HWY 550 due to convective snow in the Uncompahgre Gorge and westerly winds effecting visibility. This advisory expired late Tuesday night, however the break in storm conditions did not last long. 19 hours later Storm #17 rolled in to western Colorado from the Pacific Northwest. This storm can be characterized by cold temperatures, high moisture content, and slightly higher wind speeds (average 19 mph) compared to Storm #16.  Storm 17 wrapped up late last night.

Storm 17 lasted 61 hours and at least 1 mm of precipitation was recorded 35 of those hours, for a total of 1.6” water.  Over the past 11 days beginning when the atmospheric river first rolled into Colorado, we have received 4.5” of water with 26” of snow accumulation at SASP and 24” even at the higher wind effected elevation of SBSP.  Over the past 23 days of February, 16 days brought precipitation to Senator Beck totaling 6.5” of water.  It has been very impressive watching the NRCS SWE plots go almost vertical during this timeframe.  For the moment the Rio Grande and San Miguel/Dolores/Animas/San Juan Basins are showing slightly more snow compared to median than basins in Northern Colorado, I am trying to remember the last time this happened.

The Southwest is now enjoying a bit of sunshine and warmer daytime temperatures that typically characterize the San Juan Mountains.

Please see below for snow and precipitation graphics from SBB and NRCS.  And also please see storm reports #16 and #17 attached.

More Soon

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After a 9 day period of high pressure from Jan 25 – Feb 2, winter weather returned to the North San Juan Mountains and much of Colorado. It has been an active past four days of precipitation starting on Sunday, February 3rd with Storm #13. This was generally a warm storm with rain at lower elevations.  Over a 16 hour duration it delivered 16 mm (0.6”) of precipitation with 14.6 cm (5.7”) snow accumulation and strong winds averaging 26.9 mph with gusts up to 56.5 mph mostly out of the S-SW. Visibility during the day on Sunday was spotty due to blowing snow, a trend which continued into a blustery Storm #14.

Storm #14 has now wound down after orographic snowfall and cold temperatures overnight.  This storm was a keeper.  From early morning Monday Feb 4 to early this morning, Feb 7, we recorded 35 mm (1.4”) precipitation with 25.5 cm (10”) new snow accumulation at SASP and 19 cm (7.5”) at SBSP.  Strong winds stuck around pretty much the duration of this storm as well, with an average of 29.9 mph with gusts up to 66.8 mph, moving the snow around the landscape constantly.

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So over the last few days we received 2” of water at Senator Beck.  We have a long way to go but for now all of Colorado’s major basins are at 100% of median or better. Hopefully the skies won’t be clear for long with the next weather system arriving on Saturday night, there will be a lull however with the main portion of this Pacific trough arriving Monday afternoon through Tuesday.  This active weather pattern is expected to continue for the foreseeable future (~3 weeks).

Please see Storm #13 and Storm #14 Reports attached.  And images below,

More soon

Storm #10 (Jan. 17 – Jan 18) was a wonderful dumping of snow, closing 550 in both directions. This was rather a high intensity event, bringing 31 mm (1.2”) of precipitation over 27 hours at SASP.  Average precipitation intensity (precipitation/duration) was 1.15 mm/hr with max hourly precipitation reaching 5 mm (0.2”).  This storm also had strong winds mostly out of the N-NW redistributing the newly fallen snow.  Gusts reached 70 mph at Putney station, the fact that SASP gained ~10″ and SBSP gained 3.7″ snowdepth after it was all said and done is testament to the vast redistribution of snow mainly above treeline.  This gave CAIC and road crews a lot to deal with.

Since the latter part of November storm systems have moved through pretty regularly bringing between 12 mm (0.47”) – 52 mm (2”) precipitation.  We have received about the average number of storms so far this season and after this past storm sit on an average snowpack in terms of SWE.

Avalanche Fatality Report: The final CAIC report on the avalanche fatality at Red Mt. Pass has been published on the CAIC website: https://avalanche.state.co.us/caic/acc/acc_report.php?accfm=inv&acc_id=685

It is important that anybody who spends time in the backcountry read this report.  It highlights the crucial role of being informed, and integrating and acting on information in avalanche terrain.  If you haven’t heard, on January 5 a skier was caught, buried, and killed in an avalanche in Upper Senator Beck.  The skier was part of an avalanche level 2 field class with Silverton Avalanche School – not affiliated with CSAS. In all, six people were caught in the avalanche and five people made it out ok.

Snow School: There is still space available in our Snow School for Water Professionals, our two and half day combination classroom and field class designed for water professionals wanting to learn more about snow and our mountain systems.  Please contact me with any questions.

Please see Storm #9 and Storm #10 windroses and summary attached.

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Another storm, our third in the last week, has now left Colorado. Since Christmas Eve we have received 52 mm (2”) of precipitation at SBB.  Storm #7, arriving early December 31 and departed early evening January 1.  This storm greatly benefitted the southern part of the state.  The Upper Rio Grande and San Miguel/Dolores/Animas Basins both advanced 10% closer to median SWE.

As the below plots show we have received about average precipitation (and resulting SWE) as of the end December at Red Mt Pass.  But Red Mt is a bit of an anomaly as SNOTEL stations around the San Miguel/Dolores/Animas Basin are consistently showing mostly between 35%-89% of median with the Basin overall reporting 71% of median SWE.  Similarly, the Rio Grande Basin received a nice bump from this passing storm and four SNOTEL’s are showing 100% of median or much better, but eight are below median with the average being 76%.  The Gunnison Basin advanced 2% to 91% of median from this last storm.  And thankfully the rest of Colorado’s major basins are currently above 100%.  No dust-on-snow has been observed at SBB to date, and if history holds, we have not received a dust event in January in our period of record starting 2005.

Greetings from Silverton,

An active weather pattern started bringing precipitation to Southern Colorado the day before Christmas (bringing 0.47” water with 7.5” accumulation), took a 24 hour break, and began again the afternoon on Christmas Day (bringing 0.71” water with 7” additional accumulation).  The current system in our area has moved along by early this morning.  Another system is expected arrive midday Sunday for the Park and Gore ranges with precipitation starting Sunday night in the San Juan Mountain area and exists by Wednesday, followed by dry and cool weather through the end of the week.  Please see images below.

Please see links to Storm #5 and Storm #6 Reports.

More Soon

November Recap:  The first 5-days of November started out nicely with 26 mm (1.0”) precipitation, which constituted Storm #1 at Senator Beck Study Basin (SBB).  However the 18 days that followed we observed only 9 mm (0.35”) precipitation.  Thankfully, complex multiple frontal systems came through the Western U.S. resulting in 2 significant storms systems occurring Thanksgiving Day and then two days later on November 24.  The precipitation from these two events totaled 21 mm (0.83”) at SBB (CSAS Storm #2).  Overall boosting Mountain snowpack 8-10%, although the Upper Rio Grande mostly missed out on this round of precipitation, only gaining 1%.  But the month wasn’t over, the last day of November a low pressure trough that dipped south enough on southwest flow to give the San Juans a good shot of precipitation, 34 mm (1.3”) over a 4 day period to make it Storm #3 in the study basin.

Coming Week:  The short-term forecast is calling for a weak trough to move across the area today thru tonight bringing scattered snow in the mountains.  A more optimistic trough will move in Wednesday in the Northern Rockies and by the afternoon the trough will dip south with a strong jet moving over southern UT and the Four Corners region, resulting in 4” in the Northern San Juans and 1” in the Southern San Juans.  By latter Thursday a ridge builds in the West keeping things dry and sunny. This ridge breaks down late Friday but the next trough is expected to stay north.  But it’s nice to active weather so far this winter season, compared to last year at this time we were stuck under the wrong end of a high amplitude blocking pattern (the Ridiculously Resilient Ridge) that shut down storm activity in Colorado, and routed storms north of Colorado.

Seasonal Forecast:  The current NWS seasonal forecast has 80% chance of a weak to moderate El Nino this winter and 55-60% chance of it continuing through spring.  This type of El Nino (Modoki) seems to have the best analog in the 2006/07 and 2014/15 winter seasons, with 2014/15 being the better.  In both years, most of Colorado was at or above snowpack by mid-winter, then crashing in late winter with most of the state having below average snowpack.

Snow School:  There is still space available in our Snow School for Water Professionals, our two and half day combination classroom and field class designed for water professionals wanting to learn more about snow and our mountain systems.  Please contact me with any questions.

Please see Storm #2 and Storm #3 Reports here

Greetings from Silverton,

A number of active weather patterns have passed through Colorado over the last few weeks giving the Colorado snowpack a good jump on the season.  In October we recorded 20 days with precipitation along with the first 6 days of November.  Our first storm since we experienced permanent snowcover in the majority of Senator Beck Basin occurred Nov. 4-5.  Our definition of storm, which determines when we issue a storm report, is at least 12 mm (0.47″) of precipitation with no break in precipitation longer than 12 hours. We have received a number of recent events that just fell short of meeting that threshold, such as on Nov. 3 and Oct 30 we received 11 mm (0.43″).  Since the start of Water Year 2019 we have recorded 157 mm (6.2″) of precipitation (the average is closer to 4.3″).  And this is the theme throughout the Colorado mountains, above average snow accumulation is laying down the base for the rest of the snow season.  Unfortunately, the forecast is calling for a general drying and warming trend with any new system bringing minimal moisture, thus not much rain/snow expected.