The questions people actually ask about Bear Lake, answered from the same cited research that grounds this Watch's chat — and the chat can go deeper on any of them.
Bear Lake at State Park Marina (USGS) is at 5912.21 ft (UP&L (PacifiCorp) datum), down 1 ft over 30 days — 2.5 ft below the normal operating range.
The Bear Lake Data Watch dashboard shows live water level for Bear Lake with full historical context, tributary inflows, weather on the water, curated news and photos, and a grounded AI assistant that answers questions from the live data on the page.
The Caribbean-blue color is chemistry, not a trick of the eye. The USGS describes Bear Lake as calcium carbonate type water, and billions of microscopic suspended carbonate particles scatter the shorter blue wavelengths of sunlight back to the surface while the water stays remarkably clear. The effect is strongest on calm, sunny days over the sandy shallows.
Four species live nowhere else in the world: the Bonneville cisco, the Bonneville whitefish, the Bear Lake whitefish, and the Bear Lake sculpin, plus a distinct Bear Lake strain of the native Bonneville cutthroat trout. According to Bear Lake Watch, these species arose through long geographic isolation, evolving over thousands of years to match the lake's unusual water chemistry, structure and climate.
Each January, Bonneville cisco gather in huge schools and move into the rocky shallows to spawn, famously at Cisco Beach on the eastern shore. It is the one place in Utah where a handheld dipnet is legal for game fish: the net opening may not exceed 18 inches, and the daily limit is 30 cisco. A valid Utah or Idaho fishing license lets you fish both states' portions of Bear Lake.
Bear Lake is a natural, tectonic lake that sits in a fault-bounded basin still subsiding today. Wikipedia notes it is at least 250,000 years old and could be several million years old, and Bear Lake Watch calls it the oldest continually wet lake in North America. Estimates vary widely, so treat any single number as a floor rather than a precise age.
Not naturally: the river originally flowed past the basin without entering it. Beginning in 1911-12, developers diverted the river toward the lake; Stewart Dam, completed 1913, sends water through the roughly 6.5-mile Rainbow Inlet Canal, and the Lifton Pumping Station, completed in 1917, pumps it back out. PacifiCorp operates the system, so the lake is natural but its water level is managed.
Through the Bear River Compact, carried out since 1958 by the Bear River Commission, whose stated purpose is an equitable apportionment of the waters of the Bear River among the compacting states. Nine commissioners govern it, three appointed by each state's governor, plus a non-voting federal chair appointed by the President. The compact sets how much each state may divert and store, including in Bear Lake.
As of September 3, 2026, Bear Lake is at 5,912.21 ft, 10.21 ft above the all-time record low. Because Bear Lake works as a reservoir, its surface rises and falls within a defined 21.65-foot band, from full pool at 5,923.65 feet down to 5,902.00 feet. The record low of 5,902.00 feet was first touched on November 9, 1935, in the 1930s drought, and nearly matched in 2004 at about 5,903 feet. Wide exposed beaches mean a drought drawdown, not a permanently shrinking lake.
Bear Lake covers about 109 square miles, split almost evenly between Utah and Idaho, and stretches more than 20 miles long by roughly 8 miles wide. Its maximum depth is about 208 feet, on the deeper east side off South Eden, with an average depth of about 94 feet. That depth and volume slow how fast it warms and freezes and give its endemic fish cold, deep water year-round.
In some winters, but not every year; its depth and volume make it slow to lock up. VisitUtah says the lake freezes over seven out of every 10 years, though other local sources caution that complete freezes have become less frequent in recent warmer years, so treat that figure as a rough average, not a guarantee. Ice safety depends on real conditions, not the calendar.
Built by Daniel P. Ames, PhD — Civil & Environmental Engineering.