Following a highly variable winter, scientists from the National Oceanic and Atmospheric Administration's (NOAA) National Weather Service (NWS) expect drought concerns to continue in parts of the West, while less snow and warmer conditions in the upper Midwest foretell a lower than normal risk of snowmelt flooding this year. NOAA is part of the U.S. Department of Commerce.
"There is neither an El NiÃ±o nor La NiÃ±a in place; therefore, we expect a typical level of springtime variability in temperature and precipitation to occur in many areas of the nation," says retired Navy Vice Adm. Conrad C. Lautenbacher, NOAA administrator.
This spring NOAA scientists also expect long term precipitation deficits to decrease in parts of the northern and central Great Plains, while the hydrological drought or water supply deficits are predicted to persist over many areas in the West, especially in much of Arizona and New Mexico. Dry soils from up to five dry years will absorb snowmelt runoff and reduce recharge of reservoirs, many of which are well below normal levels as a result of this multi-year drought.
Snowpack and snow water content have been running close to normal during this winter snow season in the Great Basin and Northwest, but continued improvement in water supplies throughout the West depends largely on snowfall continuing into spring. In many cases, the meltwater will not be enough to replenish depleted reservoirs.
Overall, the 2004-fire season is expected to be near normal in terms of the expected number of fires and acres burned. However, according to the National Interagency Fire Center (NIFC) in Boise, Idaho, which issues the annual National Wildland Fire Outlook, much of the interior West, and particularly the Southwest, has above normal fire potential due to the long-term drought conditions. Drought-stressed and/or insect-damaged vegetation continues to increase in the West, leading to a greater potential for large, destructive wildfires at middle to high elevations.
NOAA officials said that with the tropical Pacific Ocean featuring neither El NiÃ±o nor La NiÃ±a during this past winter, the jet stream and its associated weather conditions were highly variable. Yet, the 2003-2004 winter weather pattern did, in fact, improve drought conditions in many locations. Nevertheless, NOAA cautions that improvement does not mean total relief.
As it stands, NOAA's U.S. Drought Monitor has very limited drought depicted east of the Mississippi River. However, it is another story for many places in the West.
"Fifty percent of U.S. states west of the Mississippi River are in some phase of dryness or drought, with the worst occurring in parts of Arizona, New Mexico, Idaho and Montana," said Johnson. "The series of winter storms seen in the Rockies since last autumn have not made up for the substantial precipitation deficits that extend back four or five years. Snowpack in the region this spring is generally improved from last year, providing hope for limited water supply improvements and better prospects for farmers and ranchers."
"Despite periods of record cold and warmth, as a whole, the 2003-2004 winter season (December through February) will go down in the record books as near average for the nation," says Tom Karl, director of NOAA's National Climatic Data Center in Asheville, N.C. "The Eastern U.S. was cooler than average while warmer than average conditions affected much of the rest of the country. While there were periods of unusually heavy rain and snow in parts of the country, including above average precipitation in some parts of the West, precipitation was near average for the contiguous U.S."