• March 2012 temperatures in Colorado were well above average ranging from 4-8 degrees Fahrenheit above normal, with highest temperatures recorded in the eastern plains and foothills. March 2012 was the 3rd warmest March on record for the period 1895-2012.  The warmest March ever recorded in Colorado occurred in 2004, followed by the 2nd warmest March in 1910.
            
  
• March is typically one of Colorado’s snowiest months.  However, Colorado in March 2012 tied 1966 for the driest on record, with records dating back to 1895.  Many weather stations throughout the state reported an extreme lack of moisture.  The Front Range and western most portion of the eastern plains were the driest of all.  The exceedingly warm and dry March conditions in Colorado are part of a large-scale phenomenon that has occurred throughout much of the continental United States.
   
  
• To date, April temperatures have been 2-8 degrees Fahrenheit above average for most of Colorado, with multiple areas experiencing temperatures 10 degrees above normal.   
       
  
• For the Water Year so far (October 2011 – March 2012) driest conditions are being reported in Northwest Colorado. 
  
  
• Colorado Climate Center weather stations for the month of March report above average moisture conditions for Walsh, near average moisture conditions for Boulder, Fort Collins, Akron, Burlington, Mesa Verde, and Pueblo; and below average moisture conditions for Grand Lake, Grand Junction, Montrose, Del Norte, and Alamosa.   
  
  
• In contrast to 2009 and 2010, dust on snow events in Colorado for both 2011 and 2012 have been relatively mild with minimal impact on snowmelt.  Significant dust on snow events were recorded in both 2009 and 2010 which led to a significantly earlier melt out of our snowpack. 
  
  
• As of April 17, 2012 US Drought Monitor, 95% of Colorado is experiencing some level of drought classification, and 26% of the state is now characterized as experiencing severe drought conditions.  D1, moderate drought, conditions remain in much of the Arkansas River basin and the northern and central mountains, while D2, severe drought, conditions have been introduced in the northwestern part of the state and the Upper Rio Grande River basins.  D0, abnormally dry, conditions account for the rest of the impacted areas of the state (35%).  Removal of D0 on the central plains and a reduction of D2 in the southeastern plains resulted from early April storms that brought substantial precipitation.  D0-D4 represents abnormally dry, moderate, severe, extreme and exceptional drought conditions respectively.
  
  
• On the West Slope, combinations of prevalent fine fuels and the possibility of a drier than normal season could lead to significant fire potential concerns as the season progresses. 
  

The 2012 Water Year

• October – Well above average precipitation in all basins.  Upper Rio Grande, Arkansas and South Platte basins had above average Snow Water Equivalent (SWE) also.  All other basins had below average SWE.
  
  
• November – Cumulative precipitation was near or above average in all basins.  November was drier than average across the state, except for in the Yampa/White basin.  Statewide, SWE was tracking along at average until the last week in November when conditions dried up ending  with November below average.
  
  
• December – DRY across the state.  The only basin to experience average precipitation during December was the Upper Rio Grande basin.  The Yampa/White recorded only 29% of average precipitation.  SWE as of January 1 was below average in all basins.  The Arkansas and Upper Rio Grande basins were near average (approximately 90%).  Yampa/White basin was at only 57% of average.
  
  
• January – Dry until January 16th across the state.  The Gunnison and Colorado basins saw well above average snowfall the last half of January.  All other basins returned to typical accumulation.  February 1 measured SWE was still below average in all basins.  Southern basins had dropped 13-15 percentage points since January 1.  Precipitation in Gunnison and Colorado River basins was near average in January, and all other basins were below average. 
  
  
• February – Experienced near or above average snowfall and precipitation across the state.  The Colorado and Upper Rio Grande basins reported snowfall totals at 97% of average.  Boosted snowpack totals in all basins with greatest increases in the Yampa/White and San Juan basins.  Statewide snowpack increased by 9 percentage points.
  
  
• March – Extremely DRY month!  Little to no additional snow accumulation across the state.  All basins snowpack percentages decreased significantly and look to have reached peak SWE in early to mid March, two to seven weeks early!
  
  
• April – Not quite as dry as March.  However, most basins are still reporting below average precipitation so far this month with the exception of the Arkansas basin.  Stream flow forecasts across the state have dropped 20-50 percent from those issued on March 1 and are still decreasing.  The Yampa/White/North Platte and Colorado River basins are fairing the worst with snowpack’s below 50% of average and very low stream flow forecasts.
  

Statewide Water Conditions:

• The statewide snowpack has declined from 52% of average (snow water equivalent) on April 1 to 39% of average on April 17, 2012.  (As of  April 25, 2012 the statewide snowpack has declined to just 31% of average).  All major river basins in the state have experienced a decline in snow water equivalent since April 1, and all continue to be below average.  Our average peak date for reaching 100% of snow water equivalent throughout the state is April 12.  However, in 2012 Colorado achieved only 68% of its peak snow water equivalent, and this peak occurred 31 days early on March 12.  For 2012, the peak snow water equivalent was achieved 50 days early in the South Platte basin, and 41 days early in the Yampa, White, North Platte basin.  Other remaining basins achieved their peak snow water equivalent ranging from 21 to 34 days early.  Colorado’s 2012 snowpack is projected to melt out completely sometime in May.    
  
  
• Colorado’s April 1, 2012 snowpack per basin is as follows: Colorado basin 49% (lowest ever), Yampa/White basin 47% (lowest ever), Arkansas basin 56% (2nd lowest ever), Upper Rio Grande basin 53% (3rd lowest ever), Gunnison basin 56% (3rd lowest ever), South Platte basin 55% (5th lowest ever), and San Miguel/Dolores/Animas/San Juan 54% (5th lowest ever).  Colorado’s April 1, 2012 statewide snowpack of 52% of average represents our 2nd lowest April 1 snowpack on record.  The period of record is from 1968-2012.
  
  
• October 2011 to February 2012 Total Water Year Precipitation for Colorado is below average for all basins so far and is the lowest in the Colorado River basin (69% of average).  The cumulative statewide precipitation average is currently at 75% of normal.
  
  
• Fortunately, statewide reservoir storage is currently at 108% of average, and is good for all basins except for the Upper Rio Grande and Arkansas basins.   The Upper Rio Grande basin has the lowest reservoir storage level in the state at 69% of average.
  
  
• The NRCS April 1, 2012 stream flow forecast continues to project below average to well below average runoff for all major streams within the state.   Stream flows are projected to range from 41-62% in the Arkansas basin, 47-74% in the Upper Rio Grande basin, 36-67% in the Gunnison basin, 45-73% in the South Platte basin, 42-67% in the Colorado River basin, 20-55% in the Yampa, White, North Platte basin, and 47-69% in the San Miguel, Dolores, Animas, San Juan basin.  The lowest stream flow forecast of 20% is for the North Platte River near Northgate.
  
  
• The statewide Surface Water Supply Index (SWSI)* values for March (April 1) range from a high value of +0.7 in the South Platte Basin to a low value of -4.0 in the Yampa/White Basin.  All seven of the basins (Arkansas, Upper Rio Grande, Colorado, South Platte, Gunnison, Yampa/White, and San Juan/Dolores) experienced a loss from the previous months value.
  
  
• *The SWSI is developed by the Colorado Division of Water Resources and the Natural Resources Conservation Service and is used as an indicator of mountain-based water supply conditions in the major river basins of the state.  It is based on snow pack, reservoir storage, and precipitation for the winter period of November through April (December 1 through May 1).  During the winter period, snowpack is the primary component in all basins except the South Platte basin where reservoir storage is given the most weight. 
  

Listed in the following table are reservoir storage and precipitation conditions as of April 17, 2012.  

Basin	Snow Pack (% of Average)	Reservoir Storage (% of average)	Total Water Year Precipitation (% of average)
South Platte	52%	104%	78%
Arkansas	45%	86%	83%
Upper Rio Grande	45%	69%	91%
San Miguel, Dolores, San Juans, Animas	39%	111%	85%
Gunnison	47%	122%	77%
Colorado	37%	120%	69%
Yampa, White, North Platte	41%	128%	70%
Statewide Conditions	39%*	108%	75%

*April 1 statewide snow pack at 52% of average snow water equivalent. 

Forecast (copied from Klaus Wolter’s Executive Summary) April 18, 2012. 

• La Nina ended up weaker than last year, and did not leave all the typical footprints.  For Colorado, an overall drier season was correctly anticipated based on typical 2nd year La Nina outcomes.  A full transition to El Nino has become more likely, but still not guaranteed.  
  
  
• A dry La Nina March was typical for La Nina.  While April can be fairly wet even during La Nina conditions, 2012 has not been too promising (if wetter than March).  There are some modest indications that the end of April will see wetter weather.  
  
  
• My forecast for late spring (April-June) shows a tilt towards dryness covering southwest Colorado, near-normal moisture over the eastern plains, and a slight tilt toward wetness in northwest Colorado.  There is a realistic chance that we could see a rapid transition toward El Nino within the next few months in which case our prospects for a wet spring would be better.  
  
  
• Bottom line: Aside from a few extreme (for La Nina) snowstorms along the northern Front Range this winter, and dryness from December into early January in the mountains, this winter did bring many of the expected La Nina impacts.  This includes more than our fair share of windstorms, as well as a warm and dry March.  The remainder of spring and summer will be much more likely to end up on the wet side if we actually switch to El Nino soon.  At present I put the odds for this at 40%.
  

Abbreviated Basin Updates (From Division of Water Resource’s Water Supply Conditions Report Dated February 2012):

S. Platte – Reservoir storage for Dillon, Horsetooth, Eleven Mile, Cheeseman, Jackson, and Barr Lake reservoirs was 115% of normal as of the end of March.  Cumulative storage in the major plains reservoirs: Julesberg, North Sterling, and Prewitt, is at 99% of capacity.  Cumulative storage in the major upper-basin reservoirs: Cheeseman, Eleven Mile, Spinney, and Antero is at 93% of capacity.  Flow at the gaging station South Platte River near Kersey was 675 cubic feet per second (cfs), as compared to the long-term average of 691 cfs.  Flow at the Colorado/Nebraska state line averaged 422 cfs, as compared to the long-term average of 520 cfs. March proved to be an extraordinarily dry month in the South Platte basin.  Greeley recorded no measurable precipitation and ended March at 27% of average precipitation for the January through March period.  Snow pack also went the wrong way in March, with snow water equivalent declining from 88% of average on February 29 to 57% of average on April 2.  For comparison, the April 2, 2002 snow water equivalent for the South Platte basin was 52% of average.  Stream flows at the Kersey and Julesberg index gages also reflected the dry conditions.  The Kersey gage went from 132% of average for February to 98% of average for March.  The Julesberg index gage went from 183% of average for February to 81% of average for March.  The South Platte main-stem moved from free river to a call from the Hewes Cook Ditch near Platteville on March 23 and remained under call from that location the rest of the month.  The main-stem also went under call from Julesburg or Prewitt Reservoirs from March 27 through the end of the month.  Calls senior to the main-stem calls continued or came on the Cache la Poudre, Big and Little Thompson Rivers as well as Saint Vrain, Boulder, Clear, and Turkey Creeks in March.  The April-June National Weather Service outlook for the South Platte basin is for below average precipitation and equal chances of below or above average temperatures.  On the brighter side, the longer term forecasts show the South Platte basin conditions shifting to equal chances of above or below average precipitation but warmer than average temperatures, until late summer when the chances for precipitation shift to above normal.   

Arkansas – Flow at the gaging station Arkansas River near Portland was 366 cfs, as compared to the long-term average of 385 cfs.  Storage in Turquoise, Twin Lakes, Pueblo, and John Martin reservoirs totaled 94% of normal as of the end of February.  Total distributed reservoir storage following the Pueblo Winter Water program was 125,870 acre-feet including 42,157 acre-feet in Pueblo Reservoir, 66,775 acre-feet in off-channel reservoirs, and 16,938 acre-feet in John Martin Reservoir (after distribution to accounts).  Conservation storage in John Martin Reservoir through March 31, 2012 totaled 19,065 acre-feet.  Although the Arkansas River basin has consistently had one of the highest percentages of snowpack among the various river basins, the statewide outlook remains poor and a great deal of concern exists about snowmelt runoff for diversions of native water within the basin and for opportunities to import water via the Fry-Ark Project, Twin Lakes and Homestake Tunnel Systems as well as through the various other trans-mountain diversions.

Rio Grande – Flow at the gaging station Rio Grande near Del Norte averaged 421 cfs (157% of normal) during March.  The Conejos River near Mogote had a mean flow of 150 cfs (191% of normal). Flow at the state line was 144% of normal.  Throughout the upper Rio Grande basin, stream flow during March was well above normal due to the abnormally high temperatures.  Storage in Platoro, Rio Grande, and Santa Maria reservoirs totaled 98% of normal as of the end of March.  Weather conditions in the San Luis Valley were much warmer and drier than normal during March.  For several days, the maximum daytime temperatures reached or exceeded the 70-degree mark and record high daily temperatures were set for six days in Alamosa during March.  Snowfall on the Valley floor totaled less than 1.0 inch, one of the worst snowfall winter months since 1970.  Alamosa received a paltry 0.10 inches of precipitation during the month.  National Weather Service forecasts call for warm and dry conditions in the San Luis Valley for the next 90 days.  Most streams in the basin began some snowmelt runoff approximately March 24 prompting the Division Engineer to open the irrigation season earlier than expected for the LaJara, Culebra, Rio Grande, and Saguache Creek drainages.  Even with the poor forecasted runoff, fulfilling the delivery obligation to New Mexico will require slight curtailments of water available to diverters in the Rio Grande and Conejos systems.  Based on the current forecast, there will be curtailments of available native water available to surface water right diverters of approximately 9% on the Rio Grande and 6% for the Conejos River system this irrigation season.  Water users should expect drought-like conditions this spring and summer.  The Valley’s aquifers will continue to decline as well pumping replaces water normally available from snowmelt and rainfall.     
       
Gunnison – Flow at the gaging station Uncompahgre River near Ridgway was 71.8 cfs, as compared to the long-term average of 62.0 cfs.  Storage in Taylor Park, Crawford, and Fruitland reservoirs totaled 107% of normal as of the end of March.  March weather in the Gunnison basin was similar to the rest of the state, extremely dry and warm.  In fact, average precipitation in the basin was 35% of normal with some areas, like Crested Butte, receiving a record low 15% of average precipitation during March.  This caused a precipitous drop in Gunnison basin snowpack to 62% of the 30-year average on April 1st.  March temperatures of 3-5 degrees above normal produced April 1st snowmelt rates of up to 0.7 inches per day, melting over five inches of snow water equivalent (SWE) in drainages above Paonia and Taylor Park Reservoirs by April 5th.  In some streams, such as Muddy Creek above Paonia Reservoir and the San Miguel River, it appears that the spring stream flow peak has already occurred, two months ahead of normal.  Both of those steams may have peaked around March 28th.  Natural Weather Service (NWS) climate forecasts predict less than average precipitation and greater than average temperatures for the next 90 days.  As of April 8th we have passed the typical snowpack peak in the Gunnison basin and have less snow than at the same time in 2002.  Reservoir storage in the basin remains at average in most areas, therefore, water users with storage will be less affected by the poor snowpack conditions.  However, calls have already been received in some areas and because steam flow forecasts predict significantly less than average flows we are expecting an early and long administration season in the Gunnison and San Miguel basins.  Many water users are hoping for April storms and an early start to the monsoon season to boost flows early this summer.  Forecasted inflow to Blue Mesa Reservoir was reduced to 330,000 acre-feet on April 1st , which is only 49% of normal and would result in Blue Mesa ending up at more than 15 feet below full in 2012.  This low inflow forecast has resulted in reduced releases from Crystal Dam, producing flows below the Gunnison Tunnel of 350 cfs as of mid April.  Based on the April 1st inflow forecast, the USBS will produce a one day peak flow of 900 cfs in the Black Canyon.  Reduced releases from Crystal dam and resulting low flows in the Gunnison Gorge should produce great fishing conditions for anglers this summer.   
   
Colorado – Flow at the gaging station Colorado River near Dotsero was 1,111 cfs, as compared to the long-term average of 1,073 cfs.  Storage in Green Mountain, Ruedi, and Williams Fork reservoirs totaled 138% of normal as of the end of March.  Upper Colorado River Basin Snow Water Equivalent fell to a record low on March 18th and continues to fall with current Upper Colorado Headwaters and Roaring Fork River basin percentages at just 49% of average as of April 1st.  Near record warm temperatures are likely to drive snowpack percentages lower through April.  The resulting early runoff will maintain Roaring Fork, Eagle and Colorado River flows near average levels throughout April, despite the significant decrease in reservoir releases.  Blue River flows have and will continue to run slightly above average.  Early spring snowfall is forecast to be significantly below average in the Upper Colorado basin.  Ruedi Reservoir releases will be cut by more than 50% beginning in early April as a result of far below average snowpack in the Upper Frying pan basin. Green Mountain reservoir releases were cut in late March to accommodate maintenance operations.  Releases will be further reduced to 75 cfs – the minimum required to meet downstream senior water rights and compact demand, with Start of Fill beginning April 1st.  Upper Blue River flows will likely remain above average with significantly warmer temperatures and resulting early runoff.  Some Front Range Water Providers are taking initial steps toward potential conservation measures and/or restrictions associated with the below average snowpack levels.  Denver Water and Colorado Springs Utilities are asking for conservation.  Other, including Northern Colorado Water Conservancy District and Pueblo Board of Water Works will rely on above average reservoir storage to supply water to their customers with no anticipated curtailments or restrictions.

Yampa/White – Flow at the gaging station Yampa River at Steamboat was 293 cfs, as compared to the long-term average of 155 cfs.  March precipitation was well below the monthly average in Yampa, White, and North Platte River basins.  Precipitation for the month, as measured at SNOTEL sites operated by the NRCS, was reported at just 28% of average for the Yampa, White, and North Platte River basins.  March snowfall was only 19% of average with most falling during the first week of the month.  Steamboat Ski Resort closed for the season as scheduled on April 15.  However, the lower mountain had been closed for most of the previous 3 weeks as deteriorating snow conditions did not allow for continuous trail access to the base.  For the season the resort received just 228 inches of snow, well below average and far less than last year’s 433 inches of snow.  Stagecoach Reservoir was ice free as of April 1st.  At Steamboat Lake, the lake is ice open along the shorelines and inlets.  Fishing at inlets is reported as good.  Most of the snowpack at Steamboat Lake Park is gone and the lake is close to ice free. 

San Juan/Dolores – Flow at the Animas River at Durango averaged 425 cfs (140% of average).  The flow at the Dolores River at Dolores averaged 240 cfs (179% of average).  The La Plata River at Hesperus averaged 41.0 cfs (256% of average).  Precipitation in Durango was 0.38 inches for the month, 24% of the 30-year average of 1.60 inches.  Precipitation to date in Durango, for the water year, is 9.50 inches, 95% of the 30-year average of 9.99 inches.  The average high and low temperatures for the month of March in Durango were 58 degrees and 22 degrees.  In comparison, the 30-year average high and low temperatures for the month are 54 degrees and 25 degrees.  Precipitation (0.38 inches) was below average for the month of March in Durango.  There are 102 years out of 118 years of record where there was more precipitation than this year.   The warm temperatures at the end of the month have started the runoff season early this year.