Spring Precipitation Could Have Varying Effects with Some Extremes

Spring Precipitation Could Have Varying Effects with Some Extremes

April 3, 2009

Once again, Nebraska faces a dual problem. Parts of western Nebraska could face drought problems with below-normal precipitation this spring, while parts of eastern Nebraska face flood problems due to above-normal precipitation, a UNL state climatologist said.

Al Dutcher, state climatologist in the Institute of Agriculture and Natural Resources, said the southwestern corner of Nebraska and the entire Panhandle face abnormally dry conditions. Since October, the state has had below-normal precipitation. Without more precipitation this spring, he said, those areas may need to be upgraded to drought status.

Dutcher said fire may be a risk in western Nebraska, too. Last year was wet, but wasn't followed up with heavy snowfall to compact the grass. Until good rainfall comes to help green up grasses, there is a high danger for wildfires. The risk could last two to four weeks, possibly longer without significant moisture.

But what may be good for one side of the state may not be good for the other.

"In order to see improved conditions in the west, we may have to endure flooding problems in the east," Dutcher said.

He said it's unlikely that moisture from the Rocky Mountains would pass over western Nebraska without hitting the east. Concern exists for flooding potential in south central, east central and central Nebraska because of the large amounts of precipitation during September and October. Many profiles are at field capacity or close to capacity, so additional moisture could likely cause a greater chance for runoff.

The large disparity between moisture in western and eastern Nebraska has been a trend for the past couple of springs. Dutcher said central Nebraska has higher soil moisture levels than at this time last year, but it's tough to tell if flooding will become a problem because it depends on the quantity and intensity of spring precipitation.

The area is coming out of a second consecutive winter with La Nina conditions and statistical analysis of past precipitation point toward a drier than normal trend, he said. The tendency across the state for May is for temperatures to average above normal and precipitation to remain below normal. Dutcher said the southwest corner and Panhandle are on the fringe of a region expected to have above-normal temperatures.

"These are weak tendencies," he said, "but our biggest fear is that each month continues this trend and the cumulative effect builds as we get into the summer."

Another point of concern is the dramatic temperature swings throughout March. Some days were 20 to 30 degrees below normal while others were 20 to 30 above normal. As storm systems move through the state in April and the state endures even more temperature swings, there is a risk for later than normal freezing.

"Big swings instead of a gradual rise in temperature can cause plants to break dormancy and promote rapid, early-season growth," Dutcher said.

An extended warmup followed by a strong cool down could set up freezing conditions and affect alfalfa, wheat and emerging spring-planted crops. Nebraskans could see damage to horticultural crops such as flowers, shrubs and non-native trees. Dutcher said non-native trees aren't accustomed to temperature swings and could suffer a considerable amount of damage.

Though many parts of the state may face adversity, Dutcher credits Nebraska farmers and producers for emphasizing the creation of no-till environments for the last decade. He said the switch to no-till has helped to reduce flooding potential and soil erosion.

"If we had these periods of heavy precipitation 10 years ago, we would've had a higher flood risk," Dutcher said. "The soil structure has improved dramatically over the years."

Asher Ball
IANR News Release