VSF Weather Blog
"Arizona's Perfect Storm - January 2010"
by Jerry Madero (posted March 2010)

The warnings began early, more than a week ahead. Northern Arizona's weather was going to change in a big way! The Weather Channel of course was just talking about California. I believe that most of the time they don't know Arizona exists since if and when the weather for the West is presented their commentator is usually planted directly in front of our state. But I digress. Local radio and TV stations were also a twitter as maps of El Nino activity and diagrams of storms that were lining up in the Pacific were displayed with numbing regularity. The National Weather Service in Flagstaff was right on top of things also and was seriously predicting phenomenal snow totals in the high country, particularly in the San Francisco Peaks area and the White Mountains. Extremely heavy rains of up to five inches were predicted for the Yavapai County valleys and basins. This was shaping up to be the biggest weather event in Northern Arizona since I rode into town a little over a decade ago. But... I'd heard it all before.

Owning a weather station one occasionally likes to see actual weather happening, something besides sunshine day after day. So craving something besides 40 degree daily temperature swings to record I jump to attention when these dire warnings are issued. Sort of like a golfer hearing the latest Tiger Woods rumor. Most of the time the letdown is severe as a few clouds come north from the Phoenix valley and drop a couple of sprinkles here and there, the winds pick up a little and then the whole thing moves out. The weather service usually blames the jet stream or a high pressure system for forcing the system to the North. Not this time!

The event started here on Monday, January 18th about 10:15 in the morning with a light shower followed by more showers that dropped modest amounts of rain on and off for most of the day. The daily total for the 18th was .35 inches. Nothing to write home about yet but things were just getting started and the dire predictions were still out there. I was still hopeful.

Another light shower began dropping rain just before midnight of the 18th and carried over into the early morning hours of Tuesday the 19th. Then all rain activity ceased until late Tuesday afternoon when a light, steady rain began and lasted for about five hours. The rainfall total for the 19th was .98 inches. Not bad, a tad over an inch and a third for the two days. The cynic in me started to waver; maybe this was going to be the real deal. But once again a letdown; no precip at all for the 20th.

But then shortly before 1:00 a.m. on January 21st a light rain began falling and continued almost non-stop, except when it changed to snow for a couple of hours at 7:00 a.m., until 8:00 a.m. the following day, January 22nd. Three hours later the rain commenced again, still light, and continued until 2:00 p.m. When all was said and done on January 23rd I had logged, including the water equivalent of the melted snow, 4.23 inches of precipitation. That represents the highest amount of precip I have recorded from a single storm event since I began keeping records.

How about those dire warnings for snow in the high country and the very likely possibility of flooding down here in the valleys? Well the snow totals were massive! Arizona Snowbowl in the San Francisco peaks recorded 92 inches of snow, over 7.5 feet of snow! Some other mind numbing totals included Kachina Village - 65 inches, Grand Canyon South Rim - 55 inches, Flagstaff Airport - 54 inches, Bellmont (where the Flagstaff Weather Service Office is actually located) - 53 inches. In the White Mountains, Greer - 60 inches, Pinetop - 59 inches, Heber - 47 inches. Even Prescott accumulated up to 18 inches of snow.

As for the flooding, we dodged the bullet. First of all the rain though steady was mostly light in intensity which allowed the washes to handle it. Secondly, apparently the snow crusted in the high country and when the snow changed over to rain in some areas it didn't melt the snow as fast as predicted. While there were significant rises on the Verde River, Oak Creek and other streams and washes the lack of heavy snow melt during the storm prevented what could have been a disastrous flooding event.

Other significant weather observations from the storm include all time low barometric pressure readings which not only occurred here but across 15% of the U.S. as the storm pushed its way across the country. My low pressure reading was 29.18" which was recorded during the evening hours of January 21st. A reading that low is consistent with readings taken during hurricanes. Winds were crazy too! Indeed hurricane force winds (74 mph and up) were recorded in Apache Junction. Ajo, AZ recorded a gust of 94 mph and a Personal Weather Station similar to mine located in Summerhaven on top of Mt. Lemon near Tucson recorded sustained winds of 67 mph with gusts to 86 mph. Last but not least one possible tornado touched down in Phoenix near Desert Ridge Mall at 8:32 p.m. on the 21st.

So all in all this El Nino instigated storm was either a record or near record setting event locally, state wide and even in some parts of the country, nationally! Later on in the month, January 27, we picked up another .11 inches for a monthly precipitation total of 4.34 inches which is a mere 3.03 inches above normal. If you thought it was a little cooler than usual for a January, you're correct as temperatures averaged 2.4 degrees below normal for the month.

Holy Cow, enough of January - let's move on.

The first few days of February brought dry conditions to the Verde Valley as we recovered from the late January soaking. But on the 6th of February El Nino struck again sending another week long series of storms across the Pacific and California to us. Over the next six days we received another 0.77 inches of rain. This was a much weaker system with higher barometric pressures, lower winds and of course not as much rain. None the less i was happy to see it. Ten days later we had two days of light showers amounting to another 0.22 inches of precip. And finally on the last day of February yet another storm dumped 0.45 inches. The last storm put us above normal as I recorded 1.44 inches for the month which is 0.18 inches above the 30 year average.

The first two months combined total of 5.78 inches has given us 44% of our normal yearly total of 13.08 inches. We're off to a good start. March normally has an inch and a quarter of precip but things fall off drastically the following three months of April, May and June. Also the spring winds will start kicking up every afternoon until Monsoon which really helps contribute to the drying out process. One note, with all the rain this winter we might see a pretty good increase in insect populations. You might want to buy some mosquito repellent for this summer.