Jayson Jacoby
The Baker City Herald

Mark Ward has rarely if ever seen his family’s farm fields in Baker Valley go from boggy to bone-dry so fast.

During the first week of April the ground was still so soggy that it was a challenge to get machinery out in the fields of wheat, alfalfa and other crops.

Six weeks later there’s scarcely a cultivated acre hereabouts that isn’t being sprayed by sprinklers.

“It’s one of the strangest years I’ve seen,” said Ward, who’s been farming here for more than 30 years. “It’s a whole new mix this year.”

There are multiple culprits behind the rapidly changing conditions that have prompted widespread irrigation and greatly reduced Ward’s and other farmers’ expectations for how much water Phillips Reservoir, a key source for summer irrigation in Baker Valley, will end up storing.

The most obvious is the lack of rain.

There was no measurable rainfall at the Baker City Airport for 24 straight days, an unusually long dry spell that ended Wednesday when a meager .03 of an inch splashed into the airport rain gauge.

The abrupt shift to rainy weather continued Thursday, when 0.22 of an inch fell at the airport, and the National Weather Service predicts the trend will continue as a parade of sodden Pacific storms sweeps across Oregon over the next several days.

The arid period that spanned April and May was especially conspicuous because it followed an abnormally damp episode that started with the wettest February on record, when 1.92 inches of precipitation was recorded at the airport.

March was also soggier than average, and April reached its average rainfall of 0.80 of an inch barely halfway through the month.

But then the spigot stopped.

The ensuing 24-day dry spell was also marked by temperatures well above average on most days.

The temperature at the Airport topped 70 degrees on 12 straight days through Tuesday.

The high temperature had risen to average or above every day in May, including three straight in the 80s (Saturday, Sunday and Monday), until rainy Thursday, when the high was 55 degrees, below the daily average of 68.

The warm stretch has shriveled the snowpack in the mountains, although it remains above average in many places.

Since May 1 the snow depth at a measuring site near Anthony Lake, elevation 7,160 feet, has shrunk from 50 inches to 26.

But warm, dry weather hasn’t been the only factor.

Indeed, Ward doesn’t even think that duo deserves the bulk of the blame.

The greater villain, he believes, is wind.

Spring tends to be a blustery season, to be sure. But Ward said that nearly incessant north gales that buffeted Baker Valley on many days during the dry period played a major role.

“It has dried us out immensely,” he said. “When you have consistent 17 to 20 mile an hour winds all day you can watch it just suck the moisture out of a wheat crop.”

Researchers have shown that as wind velocity increases so does the rate of evaporation, as the wind blows away moist air near the ground surface.

During the 24 days without rain the average wind speed at the Airport topped 10 mph on 10 days, and gusts exceeded 30 mph on 13 days.

The combination of wind, heat and lack of rain prompted farmers and ranchers to start irrigating heavily, and that in turn forced the Baker Valley Irrigation District, which manages Phillips Reservoir, to release a glut of water through Mason Dam.

For most of April the district was releasing a comparative trickle from the dam. Augmented by the inflow from the Powder River and tributaries such as Deer Creek, the reservoir was rising rapidly.

Phillips, which is considered full when it’s holding 73,500 acre-feet of water, was gaining more than 810 acre feet daily in April, going from 12,700 acre-feet at the start of the month to 37,200 on April 30.

But on May 1 the irrigation district boosted the water release from Mason Dam from 42 cubic feet per second (cfs) to 167 to meet the demand from downstream irrigators.

The volume has continued to rise, reaching 345 cfs earlier this week before dropping to 310 cfs today.

That nearly equals the rate of inflow from the Powder River. And because tributaries bring in comparatively small volumes, the reservoir has been rising at a much slower rate during May — about 270 acre-feet per day, one-third the rate during April.

The bottom line, Ward said, is that Phillips, which in early April looked as though it might reach 75 percent of capacity or perhaps even higher, now probably won’t go much above its current 57 percent.

“It’s surprising and disappointing,” Ward said.

He doesn’t expect that the rainy stretch that started Wednesday will have a significant benefit because farmers will continue to need irrigation water from the reservoir.

Ward said he and other members of the Baker Valley Irrigation District’s board of directors recently made “a small wager” over how far the reservoir would rise this spring.

All the predictions were too optimistic, he said.

Ward doesn’t believe the situation at the reservoir is due solely to the high demand for irrigation water.

See more in the May 17, 2019, issue of the Baker City Herald.