Buckets of rain and two large snowstorms in the last week made a dent in Oklahoma's drought, but state officials caution that unless the wet trend continues, it may just be a respite from the costly drought.
The U.S. Drought Monitor update on Thursday showed that about 12 percent of the state was in the most severe drought category, D4 (exceptional drought). That level is down from about 42 percent last week and the lowest level of D4 since July 31.
The percentage of the state in D3, the second-most severe category, dropped from about 87 percent to 62 percent, the lowest level since July 24. The entire state is still at least in D2 (severe drought).
The majority of Tulsa County dropped to the D2 category, except for the far western and northern parts of the county.
"We looked at all the drought impacts, not just the rain amounts but that soil moisture had improved across the eastern half of the state and lake levels had gone up," said Gary McManus, associate state climatologist with the Oklahoma Climatological Survey. "That was the impetus to make the big change in the drought monitor."
McManus said the Oklahoma Mesonet, a statewide network of weather monitoring stations, showed improvements in soil levels down to 2 feet deep. It's a harder level to replenish during a drought, but it also tends to stick around longer than surface-level moisture.
"It gives something for the plants to work with down to the root zones," McManus said. "When we look at the process of ending drought, you have to have moisture down deep."
Most of that precipitation in Tulsa fell as rain with 3.18 inches of precipitation recorded last month. That makes February 2013 tied for the 12th-wettest February since 1888.
Snow events were part of the moisture in Tulsa, with 3.7 inches of snow recorded last month. That, however, is roughly 0.35 of an inch of liquid.
The snow events in Tulsa weren't nearly as monumental as some parts of western Oklahoma. Two snowstorms in a week brought more than a foot of snow to some places there.
Western Oklahoma farmers have long suffered the effects of the multi-year drought, and wheat farmers were concerned about this year's winter crop, said Mike Schulte, executive director of the Oklahoma Wheat Commission. Those concerns may have waned some with February's moisture, but much can happen between now and harvest time in late May and June, he said.
"We've been in this severe drought, so the wheat in all areas has been stressed more so than what I've seen in a long time," Schulte said.
Winter wheat tends to go through the emergence phase in late fall, Schulte said. Studies have shown that if emergence hadn't occurred in December, the yield is about half of its normal yield, he said.
"In northern Oklahoma, a lot of the wheat hadn't emerged until the last part of February, so we're way behind," Schulte said. "We're going to have to have timely rains from here on out."
He said that wheat crops in southwest and central Oklahoma are faring better than fields in the northern part of the state.
McManus said the influx of moisture to the deeper soil levels puts the state in a better condition going into the spring. Most of the state's rain typically comes in May and June and with soil moisture recharged going into spring, it can provide quicker improvement as long as the rains come, he said.
"It means we can have a little more of a cushion as we go into the spring with the soils moistened up to the two feet levels," McManus said.
In 2012, however, March had more than 6 inches of rain and was one of the 10 wettest March months on record. The rains all but stopped after that and drought conditions came back quickly, McManus said.
"This upcoming spring is vitally important to get to a rainy pattern when we head to summer," McManus said. "I have yet to see a drought end without rain."
While the immediate forecast for Tulsa is dry, McManus said another storm system is on the horizon. Yet it's still too far away to accurately predict its impact.