Dry run continues

Seasons change even when they never quite seemed to arrive, and so the next few weeks will undoubtedly bring the first hints of spring. Unless the Climate Prediction Center changes its current outlook, flooding is unlikely to play a major part in the season ahead of us.

According to predictions released by the National Weather Service (NWS), drought conditions are expected to persist this spring and there is a below average potential for flooding in this region.

The U.S. Drought Monitor is likewise expecting abnormally dry to extreme drought in the northeast of Wyoming, with those conditions predicted to persist through April. At this time, all of Crook County is in severe drought, with extreme drought in the northwestern corner.

According to NWS, current observations show there are between one and three feet of frost in the ground. However, the dry soils are ensuring that the ground remains porous despite being frozen, which has led to water infiltration into the ground throughout the winter.

At this time, the year’s snowpack is confined to higher elevations in the Black Hills and ranges from bare ground to an estimated one foot. The water content of the snow is as little as a quarter of average, with only a few inches being reported.

In the Bear Lodge Mountains and Black Hills, estimates of liquid water content range from a few inches to 18 inches, with water equivalents between 2 and 3.5 inches.

According to NWS, October was a very wet month, but the ground did not freeze until late December so a lot of the moisture disappeared thanks to the warm and windy conditions of November. January saw much less precipitation than normal for the whole area, with the only measurable precipitation coming at the end of the month – dry, mild conditions that have mostly continued into February.

Of course, March and April generally bring more snow – a third of annual totals – so the rate of snowmelt has yet to be determined. The most recent outlooks for the next couple of months give equal chance to more or less precipitation than usual.

However, La Niña is expected to continue and, according to NWS, local studies suggest that the most likely outcome will be below average precipitation this spring. The tropical Pacific Ocean continues to show below average water temperatures, which are expected to gradually warm later in the spring and transition the overall climate of the northern hemisphere to the warmer conditions of El Nino.

The NWS has released its flood outlook for river basins including the Belle Fourche and Little Missouri.

“There is a below average potential for flooding this spring caused by river ice breakup or snowmelt,” states the outlook.

“Ice cover on the streams and rivers will begin to thaw and melt over the next few weeks. The lack of snow cover, dry soils and minimal precipitation expected will limit runoff during this time period.”

February and March usually sees river ice breakup and the potential for ice jam flooding. Snowmelt flooding typically begins on the plains between March and May, but later in the Black Hills and higher elevations.

“The potential for rainfall-induced flash flooding is not quantifiable, because this type of flooding is usually caused by localized thunderstorms during the spring and summer,” states the outlook.

“The flood potential is still very dependent on weather conditions this spring. The amount of additional snow and rain, as well as the timing of peak river and stream flows, will have a significant effect on the severity of flooding.”