"Most all of the snowpack is confined to the mid and higher elevations," says Ron Miller, a meteorologist with the National Weather Service in Spokane. Precipitation in the mountains wasn't much higher than usual, he says, but little or none of it fell as rain -- which also contributes to melt-off. Measuring the weight of the snow instead of the depth, Miller says that it's about 130 percent to 140 percent of normal for North Idaho and northeastern Washington for this time of year. "If there's several days in a row of above-normal temperatures, we could see a rather quick melt of a lot of snow up there," he says. "That's why we've been monitoring the bigger rivers."
Bob Graham, incident commander for Emergency Services in Boundary County, Idaho, agrees. "It all depends on how the excess goes off, and so far so good," he says. If May weather is normal, chances of flooding along the Kootenai River are small. Heavy rains and warmer weather, however, could change things. "Those two conditions together -- bringing off 111 percent snowcap at the medium and higher levels -- could result in problems for us. But it would almost take that combination to push into where we're flooding," he says. Boundary County is heavily diked from the Kootenai River, but even before flood stage is reached, agriculture in the lowlands can suffer from a rising water table, he says.
Snowpack in the Canadian Rockies, which feeds the Columbia River, is also staying stubbornly put. This presents a special challenge, because the operators of the Grand Coulee Dam have to draw down the reservoir to make room for the impending melt-off, but they have to keep water flowing to generate power and accommodate endangered fish downstream. "Our outflow is more than our inflow, right now," says Lynne Brougher, spokeswoman for the Grand Coulee Dam. The reservoir has been drawn down to a flood control level of 62 feet beneath full-pool, leaving some boat docks high and dry. "This weekend we dipped a little below flood-control elevation, but it was back up this morning," she says. "It's really touchy right now and it's all weather dependent.
"The more snowpack is tied up for longer, the longer the drawdown will be," she says, adding that the reservoir is always filled back up by July 4.
Tom Mattern, director of Spokane County's Emergency Services, says his department has been monitoring the Spokane River. The river will be moving fast at 3,100 cubic feet per second within the next few weeks, he says, and they are expecting it to reach near flood levels. Some areas of Peaceful Valley flood when the river reaches 27 feet at the USGS flood gauge at Cochran Street. Other areas start flooding when the river level reaches 29 feet, he says, noting that he's seen nothing from the National Weather Service to indicate it will get that high.