In a season when farmers and ranchers expect to begin spring groundwork and planting, projects seem slow to start. The 2022-2023 winter has unexpectedly extended into the spring, bringing record levels of snowpack to the mountain states. As farmers work around this appreciated inconvenience, many more storms are still in the forecast, but sufficient water is likely to be available this year for the growing season.
At the close of the 2022 irrigation season, many reservoirs had once again reached almost record-breaking lows. Record-low reservoir carryover from 2021 and poor snow accumulation through February and March made for negative 2022 outlooks. The mountain states were rescued from extreme drought conditions by late rain in April and May 2022. Unfortunately, normal usage and extreme late summer temperatures once again exhausted the water supply.
With the forecasted second consecutive La Nina winter in 2022-23, sources predicted the drought would only worsen based on historical trends. Typically, Idaho basins have lower snowpack at the end of a second La Nina year.
Diverting from historical trends, snow water equivalent has reached record high levels across the mountain states. Basins throughout Utah recently broke the historical record of SNOTEL reporting stations, with the record beginning when the stations started reporting in 1980. Southern Idaho regions are also well above average at 140% and northern regions still close to average. Montana, Wyoming, and Washington are all at or above average in most of the reporting snow basins.
Water supply is increasing as snowmelt makes its way into the reservoirs. Though reservoirs are slightly under charged compared to last year’s levels at this time, the snow melt is likely to raise these levels well above 2022. However, temperature fluctuations will greatly influence the amount of water that makes it to these reservoirs. If temperatures suddenly rise and snow quickly melts and begins to flow downhill, more water will make it to the reservoir. However, if temperatures change between warm and back to freezing, more water will be absorbed into the soil and not make its way to the dams.
Idaho reservoirs still range from 24 to 62% of normal and Utah’s reservoirs are more than 10% lower than last year at this time. Nearby reservoirs in Eastern Oregon, follow similar trends with larger storage sites like Owyhee reaching 31% on March 28th, 2023 but nearby Warm Springs has only reached 13%. Irrigation district managers state that the year has the potential to have good water allotments, but the approaching snow melt leaves a lot to chance.
Despite these snowy days of March, irrigation districts are moving forward with water disbursement. Irrigation canals will be filling in the coming weeks, with the Nampa and Meridian Irrigation District (NMID) announcing April 5th as a startup date. Other canals across the mountain states are likely to see water deliveries begin in mid-April. The actual water available to the mountain states remains to be seen as winter weather eventually ends and the spring snow melt fills the reservoirs. For farmers, communities, and homeowners the availability of water after years of drought is a promise that hopefully isn’t too good to be true.