Year of weather extremes ends with plenty of precipitation
The year 2010 started and ended with major snowstorms in Prescott that helped push it to above-average precipitation in spite of a lackluster monsoon.
The December precipitation also came in spite of a strong La Niña weather event that tends to produce below-average precipitation during Prescott winters.
Government forecasters still are saying the remainder of the winter is likely to be drier and warmer than usual in the Southwest.
The strongest La Niña signal is in the January-April period, and all previous La Niña events have delivered dry winter conditions to the Southwest as a whole, noted the University of Arizona's Climate Assessment for the Southwest at www.climas.arizona.edu.
The year 2010 ended with 19.69 inches of precipitation at Prescott's official Sundog measuring site on the northeast side of the city, according to unofficial numbers from the National Weather Service. That's 104 percent of Prescott's 112-year average of 18.9 inches.
It was a major improvement over 2009, when Prescott received only 7.77 inches of precipitation. That year also produced a relatively dry monsoon.
Communities throughout all corners of Yavapai County - from Castle Hot Springs in the south to Bagdad in the west to Seligman in the north and Clarkdale in the east - also experienced above-average precipitation in 2010.
Bagdad saw an extra 5.39 inches, or 138 percent of average, ending up with almost exactly the same amount of precipitation as Prescott at 19.68 inches. That made it the 10th-wettest year in Bagdad's 81-year record.
The year 2010 also was the seventh wettest for Camp Verde with 18.4 inches, or 5.61 inches above the 72-year average; and the eighth wettest in Clarkdale, which got 16.43 inches or 4.21 inches over its 90-year average.
A two-decade warming trend for Prescott is continuing, which made the snowstorms even more unusual. The 2010 average temperature was 1 degree above normal at 54.4 degrees. Minimum daily temperatures were especially high.
Yet because of the end-of-year snowstorm, the Verde Basin currently contains more than 150 percent of its normal snowpack.
Also unusual were the series of tornados that struck northern Arizona on Oct. 6, including one in Yavapai County near Cordes Junction. Homes were destroyed in Bellemont, where northern Arizona's National Weather Service office is located.
The Weather Service called 2010 a "year of weather extremes" in its new list of its Top 5 weather events for northern Arizona in 2010.
"Weather ranged from brutal winter storms to relentless dust storms, fires, floods and even a rare tornado outbreak," the introduction to the list noted.
The extreme weather started Jan. 18-23 when a powerful storm brought record precipitation to Prescott and other parts of Yavapai County, producing dangerous flooding in Black Canyon City that inundated an RV park when the Agua Fria River crested to a record 28 feet.
Prescott got 5.54 inches of precipitation and 13-18 inches of snow from the multi-day storm, ranking it as the third-highest precipitation and third-highest snowfall event, according to the National Weather Service.
The snow fell throughout the six days with periods of rain in between. The 2.97 inches of precipitation that fell Jan. 22 was the 10th wettest day in Prescott's history.
It also was the sixth-wettest January on record for Prescott. The month made the Top 10 wettest January lists in Bagdad, Sedona, Seligman and Clarkdale, too.
The storm that literally ended the year Dec. 30-31 was colder, producing approximately 8-12 inches of snow at various elevations in Prescott, according to the National Weather Service. The official Sundog measuring site recorded 6.5 inches. Crown King recorded 17 inches.
The end-of-year storm produced snow down to about 2,000 feet in elevation and closed ice-and-snow-covered portions of Interstates 40 and 17 in northern Arizona.
Ensuing cold temperatures have kept snow on the ground in Prescott for an unusually long period of time, with large patches of snow and ice still remaining today despite rapidly warming temperatures since Friday.
The Weather Service's Top 5 weather events of 2010 also included a series of spring wind and dust storms in April and May that forced closures of Interstate 40. Wind gusts reached a hurricane-force 77 mph at the Two Guns I-40 exit east of Flagstaff on May 11. Prescott's winds topped out at 46 mph on May 23.
The Top 5 list also includes the June 20 Schultz Fire that burned more than 15,000 acres on the San Francisco Peaks and the resulting floods during the monsoon.
Despite the strong winter storms that started the year, northern Arizona dried out between mid-April and June and set the stage for dangerous wildfire conditions. It was the third-driest stretch of 100 days in Flagstaff's history.
Then after the wildfire, a powerful thunderstorm on July 20 sent muddy floodwaters from the burn area down into several subdivisions and flooded at least 85 homes. It also forced the temporary closure of Highway 89.
Prescott saw only 60 percent of its average monsoon rainfall in July through September, because of a late start and dry ending.
After a nearly bone-dry September, October came in warm and wet. It was the fourth-wettest October in the Prescott airport's 62-year history, and the 23rd warmest.
December ended the year with above-average precipitation across the region, topping out with 7.62 inches along Oak Creek near Sedona. Yavapai County numbers included 1.84 inches at Bagdad, 2.8 inches at Castle Hot Springs, 2.11 inches at Cordes, 2.33 inches at Jerome, 3.24 inches at Camp Verde, 3.01 inches at Prescott, 1.51 inches at Seligman, 2.15 inches at Clarkdale and 3.74 inches at Walnut Grove.
The last day of 2010 produced a record-low high temperature of 22 degrees in Prescott, then the first day of 2011 produced a record-low high of 29 degrees.
The South Rim of the Grand Canyon ended the year at 30 degrees below zero, the coldest temperature on record for northern Arizona on New Year's Eve.
Prescott dipped below zero Jan. 2 to minus 1 degree before temperatures started creeping back up again.
Despite the cold snap, December was the fifth-warmest December on record at the Prescott airport.
January has been dry so far, with high-pressure systems keeping it more in line with La Niña weather patterns.
"La Niña remains pretty strong," said Chris Outler of the National Weather Service office in Flagstaff.