Winter has been a pleasant diversion with plenty of snow in Arizona’s high country and rain at lower elevations. Still, the long-term drought persists, according to the members of the Arizona Department of Water Resources’ State Drought Monitoring Technical Committee (MTC).
“The wet winter has definitely been a bonanza for us,” said Tony Haffer with the National Weather Service, chair of the monitoring committee. “But the Southwest in general, and Arizona in particular, has been in deficit for many years. Naturally, it will take many winters like this one to get us back into balance.”
“Reservoirs still are refilling and long-term groundwater deficits in the state will take many years to replace,” said Tom Carr, assistant director for statewide planning for the Arizona Department of Water Resources.
“We are entering our 14th year of drought,” said State Climatologist Nancy Selover. “I believe it started after the very wet winter of 1993, which was the end of the wet period. Lakes Powell and Mead were pretty full at that time.”
The wet conditions experienced across most of Arizona over the past two months have been unusual for a La Niña event of this strength and magnitude. Intra-seasonal variability related to pulses of moisture traveling across the Pacific Ocean, in conjunction with a persistent jet-stream pattern favorable for Arizona precipitation, have produced the welcome wet winter conditions.
Precipitation totals for the “water year,” which began October 1, 2007:
– Phoenix 4.24" (.47" above normal)
– Tucson 2.97” (.21” below normal)
– Flagstaff 11.09" (1.51" above normal)
The MTC is a scientific working group that assesses drought status. It is made up of hydrologists and climatologists representing local, state, and federal agencies and organizations. This group is tasked with monitoring current drought conditions, forecasting future conditions, and communicating that information to resource managers, decision-makers and the public.
The MTC, established by Gov. Janet Napolitano’s Drought Task Force, meets each month to produce a monthly short-term drought status map, a monthly drought monitor report, and a long-term drought status map each quarter.
This information is available on the Arizona Department of Water Resources Web site at www.azwater.gov/dwr/drought/DroughtStatus.html.
The MTC met Feb. 1 to discuss current conditions and forecast likely future conditions. Based on four years of data through Dec. 31, 2007, Arizona’s long-term status is abnormally dry to severe throughout the state.
The current La Niña is expected to persist through the spring and consequently, the National Weather Service Climate Prediction Center continues to forecast warmer and drier than average conditions for the southwestern U.S.
A shift to warmer temperatures over the next two months may cause the snowpack to melt earlier than usual, limiting streamflows later in the spring. The wet winter of 2007-2008 certainly improved short-term drought conditions, but long-term drought endures.
The MTC will issue its next quarterly long-term drought status update in April.
For additional information, contact: Susan Craig at (602) 771-8533 or [email protected].