TWIN FALLS – Record-setting temperatures and low spring rainfall have led to concerns over a multi-year drought according to a report by the Idaho Department of Water Resources.
The combined average daily temperature for Idaho in June and July is now the hottest on record, which goes back to 1895.
Idaho Department of Water Resources hydrologist David Hoekema, author of the report, said the high temperatures have put a strain on the water demand.
“We ended up with really low supply, much lower than expected, and demand that you know is setting records,” Hoekema said. “So we kinda got hit on two sides.”
It was hard to prepare for the drought as the snowpack looked normal as of April 1, he said. Lack of spring rainfall and then high summer temperatures have exacerbated the problem. About 90% of SNOTEL snowpack sensors set new minimum precipitation records across the Pacific Northwest from March 1 to July 31.
The Big Wood, Big Lost and Little Lost basins may all set record lows this year according to runoff data.
The drought is leading to a depletion of reservoirs across the state which normally store water from one year to the next, Hoekema said. Carryover acts as an insurance policy.
“We are really hitting hard and using up our storage pretty strongly. So if we do go into a couple more years of drought there is potential we could see some of the worst drought, period, on record,” he said.
Idaho needs an above-average snowpack in most basins this year to recover the lost storage, he said.
On the bright side, there are developing La Nina conditions that could help the water supply, Hoekema said. During periods of La Nina the southwest sees drier conditions and the northwest gets more water.
