Drought conditions persist in western and southern Plains states
July 3, 2018
As the 2018 drought has hit hard in the western states and also in the southern Plains states, meteorologists and climatologists joined together during two webinars: June 25 and 27 to share vital updates about drought impacts.
While the hardest hit areas are southwest Colorado, northern New Mexico, as well as the Texas Panhandle (especially around Amarillo,) and the western one-third of Oklahoma including the Oklahoma Panhandle, there is at least some encouraging news in the longer range forecasts for rain.
First, the southwest states, and reasons why drought conditions began.
"The San Juan River in extreme northwest New Mexico is at the bottom 10th percentile for this time of year. However, if you look at the upper portions of the Pecos River (north of Lake Santa Rosa), and the upper portions of the Rio Grande, near Taos, they are both at record low flows for this time of year. This is directly attributable to the lack of snowfall/lack of snowpack this year, and the lack of subsequent run off," said Victor Murphy, climate services program manager, National Weather Service Southern Region.
“These levels of drought conditions are ranked in the bottom fifth percentile or lower. That means that typically in 100 years, only five years or less would be considered worse.”
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Western Colorado is (also) really hurting right now with regard to streamflows and hydrologic conditions. "Nearly all streamflows are in the bottom 10 percentile for this time of year, with some at record lows for this time of year," Murphy said.
Streamflows are low because of the poor spring runoff season after the low snowpack started melting.
"Water supplies, normally at their highest in June due to re-charge from snowmelt and runoff, were not adequately replenished, and they could experience more stress through the high demand summer season," said Becky Bolinger, Ph.D., assistant state climatologist at the Colorado Climate Center-Colorado State University in Fort Collins, during the June 25 webinar.
Western states count on a strong monsoon season (which is a seasonal reversal of the wind pattern that typically brings moisture up and into the four corners' states of Colorado, New Mexico, Arizona and Utah. "However, the poor monsoon season late last summer triggered the launch into drought conditions. This was also followed by the dry, warm beginning of (what is typically) the 'snow accumulating' season. By January, the higher elevations were experiencing what some may refer to as a snow drought. Many mountain locations in central Utah, western Colorado and northern New Mexico reported their lowest seasonal peak snowpack on record," Bolinger said.
Since the beginning of what's known as "the water year," (October 2017 through May of this year,) most of the four corners have seen much below-average precipitation and much above-average temperatures, with some locations experiencing their record driest and/or record warmest water year, to date.
"In the southwest U.S., (Colorado, Utah, New Mexico, Arizona, Nevada and California,) over 68 percent of the area is experiencing drought conditions according to the U.S. Drought Monitor. Almost 32 percent of the region is experiencing extreme (D3) or exceptional (D4) drought conditions. Exceptional drought is focused over the four corners area and extends into central Arizona and across northern New Mexico," Bolinger said.
These levels of drought conditions are ranked in the bottom fifth percentile or lower. "That means that typically in 100 years, only five years or less would be considered worse."
"All of the four corners states have widespread fire restrictions. A greater than average number of wildfires is anticipated, due to longer term drought conditions and short-term dry and windy weather," Bolinger said. She said this wildfire season has affected the recreation industry with the widespread National Forest closures in Arizona, New Mexico and Colorado. "Future impacts are expected to include the increased risk of flash flooding, as burned areas change the land cover. The vegetation can no longer take in the water, and so the ground develops a sort of 'repellent' barrier that increases runoff and causes flooding," Bolinger said.
There is however, some encouraging news that the summer monsoon could begin in earnest in the next one to two weeks. "This should greatly alleviate this," Murphy said during the second webinar on June 27, which was also hosted by the team of National Oceanic Atmospheric Administration's National Integrated Drought Information System and the National Weather Service, U.S. Department of Agriculture, National Drought Mitigation Center, and the American Association of State Climatologists. But Murphy said, if the monsoon under-performs, then going forward into the cold season, all eyes will then turn to the developing El Niño climate pattern to provide relief. El Niño, formally called the El Niño Southern Oscillation, is the opposite of La Niña.
One note of caution, this forthcoming monsoon could be good for alleviating drought conditions, Bolinger said. "In areas where spotty thunderstorms occur though, the risk of lightning starting a wildfire will be high. And in localized burn areas, there will be an increased risk of flooding."
Drought impacts include reduced forage and pasture, livestock herd reduction and the high fire danger. The combination of heat and lack of precipitation is stressing crops and threatening yields this year. "While recent pockets of heavy rain in south and west Texas, the Oklahoma Panhandle, and southwest Kansas provided some local relief, however dry conditions and record-high heat have expanded severe drought conditions in southeast Oklahoma and northeast Texas. These recent rains resulted in significant drought improvement in parts of western Oklahoma and the Texas Panhandle," Murphy said. "However, areas on the periphery (around Amarillo, and in far southwest Oklahoma along the Red River) are still in extreme drought (D3) and still in need of improvement. Short-term drought and above average temperatures could tip them back to D4 if rainfall doesn't materialize in July."
The Climate Prediction Center has issued an El Niño Watch as of June 14. "By the fall, there is a greater than 50 percent chance that an El Niño will develop, and is expected to be of moderate strength in the fall and winter," Bolinger said.
While the southwest drought conditions developed because of the La Niña occurring last fall and winter, an El Niño may help shift the pattern. "Check out http://www.esrl.noaa.gov/psd/enso/climaterisks to see what is statistically likely during an El Niño fall and winter," Bolinger said. "In both seasons, most of the region (in the four corners and extending toward the eastern plains, but especially to the south) there's a better likelihood for wet extremes to occur and it's less likely that they'd see dry extremes during this time. More wet extremes and fewer dry extremes could help chip away at the drought around the four corners. Unfortunately, that pattern weakens as you move north, when you reach Wyoming and northern Utah, that pattern is opposite and we would expect to see an increased chance of dry extremes occurring."
"Drought is never really over, especially in the western states," said Elizabeth Weight, regional drought information coordinator for NOAA's National Integrated Drought Information System. "Drought stresses ecological systems, so it can take years to recover from a prolonged drought that inflicts damage on grasslands, forests, streams and aquifers. So, we need to shift from reactive crisis mode to longer-term drought planning through, for example, investing in good soil management practices, managing groundwater resources for the long-term, state-level drought planning that supports farmers and ranchers, and in better drought predictions and forecasting."
The webinars, which are seminars presented live on the internet, were also recorded, and are available at http://www.drought.gov. ❖
— Hadachek is freelance writer who lives on a farm with her husband in north central Kansas and is also a meteorologist and storm chaser. She can be reached at email@example.com.