The 2023 Mono Lake level forecast

Each spring the Mono Lake Committee’s team of Mono Basin modelers and hydrology experts uses the lake level on April 1 together with the Mono Basin snowpack numbers and similar-year hydrological statistical data to produce the Mono Lake Committee lake level forecast for the runoff year ahead. You can download the full May 15, 2023 Mono Lake level forecast here.

At the end of last year Mono Lake had fallen to 6378.4 feet above sea level due to very dry weather and dry runoff conditions. Winter precipitation was abundant and then raised the lake to 6379.99 feet on April 1, 2023.

April 1 is the start of the current runoff year; record-high snowpack and expected record runoff classify this as an “Extreme-wet” year type. The graph below shows the range of likely Mono Lake elevations for April 1, 2023 to March 31, 2024. The range of projections is produced by the Mono Lake Committee’s modeling of hydrologic sequences using 1983, one of the wettest years in the historical record, plus an additional increment for the expected runoff volume exceeding 1983.

This forecast shows that the most probable lake level (with 1983 climate from April to September followed by a near-average winter like 1999) for April 1, 2024, is near 6384 feet above sea level.

Reference lake levels

  • Due to the record-breaking winter the Committee forecasts Mono Lake will rise a total of 5.5 feet by the end of 2023.
  • State Water Board mandated lake level to protect Mono Lake: 6392 feet above sea level.
  • Lake level rise from April 1, 2023 needed to achieve the mandated level: 12.01 feet.
  • This year the Los Angeles Department of Water & Power (DWP) is allowed to divert and export up to 4,500 acre feet of water. Next year, with the lake above 6380, DWP will be allowed to divert up to 16,000 acre feet.
  • The current “Extreme-wet” year will raise the lake 30% of the way to the mandated healthy level, however, State Water Board action is necessary to ensure this gain is not lost in subsequent years.

Top photo by Bartshe Miller.