Drought declaration means low water level for Okanagan Lake basin

The joint Canadian-American board responsible for managing lake levels in the Okanagan has declared drought conditions.

The International Osoyoos Lake Board of Control issued the declaration today, May 12, in a media release.

It’s triggered when the water flow in the Similkameen River falls below normal and one of two Okanagan Lake drought indicators are met.

This year all three have been met, which means negative implications for water supply this summer.

Water levels in Osoyoos Lake and Okanagan Lake will be kept low to lessen the ecological impacts.

Drought declaration means low water level for Okanagan Lake basin | iNFOnews.ca — Water year 2026 (bright green) and water year 2025 (dark green) Osoyoos Lake Levels, along with allowable range under the normal rule curve defined by the International Joint Commission Orders of Approval for Osoyoos Lake (solid black). Expanded drought Conditions rule curve (red dashed). For the period of record from 1987-2025, the mean daily lake level is shown as a black line, and the historical gauged minimum, 10th, 25th, 75th, 90th, and historical gauged maximum lake levels are shaded grey (USGS, IOLBC 2026).

In April, Washington State declared a state-wide drought because of the low snowpack and summer water supply concerns.

The BC River Forecast Centre May snow and water supply survey found an elevated drought risk and no risk of flooding in the Okanagan Valley.

The Okanagan basin only has 31% of the normal snowpack for this time of year and it’s the lowest on record since 1980. The Similkameen only had 61% of the normal snowpack.

The lower elevation snowpack in the Okanagan has melted early that usual so Okanagan Lake is being managed to store enough water for the expected dry summer.

Many Okanagan municipalities have already raised watering restrictions in preparation for water supply issues.