Dust storm hits Phoenix, limiting visibility
by Brittany Smith, Connor Radnovich and Matt Haldane
The Arizona Republic-12 News Breaking News Team
More storms are forecast for Wednesday evening, following a massive dust storm that swept across the Phoenix area Tuesday night, leaving a path of dust, debris and damage in nearly every part of the Valley.
Wednesday evening's forecast includes a 20 percent chance for thunderstorms in the Valley and between a 20 percent and 25 percent chance for dust storms beginning between 5 p.m. and 6 p.m., according to the National Weather Service.
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"No night is ever going to be exactly the same," National Weather Service meteorologist Craig Ellis said. "The odds of getting another (big dust storm) are not that great, but on the other hand, the conditions have not changed that much, so it's possible.
"It's possible we could get another dust storm tonight. As to how bad it could be, that's difficult to say."
A blanket of haze upwards of 10,000 feet high still covered downtown Phoenix Wednesday afternoon, caused by dust from Tuesday's storm, Ellis said. The dust will remain if another dust storm hits tonight, but could dissipate with rainfall.
The wall of dust, which originated between Phoenix and Tucson, rolled into the Valley just before 7:30 p.m. Tuesday, Ellis said. The mile-high dust storm moved between speeds of 50 and 60 mph and appeared to be nearly 100 miles wide, according to the Weather Service's radar. The dust began to settle by the time it reached Yuma later in the evening.
A typical dust storm in Arizona might reach 1,000 feet and travel between 30 and 40 mph, Ellis said.
At its peak Tuesday night, visibility fluctuated between zero to a quarter of a mile.
"I've been (in Arizona) for nearly 33 years, and I've never seen as thick a coating of dust, on streets and cars, as this one," Ellis said. "I've never seen anything like it before."
Phoenix Sky Harbor International Airport was forced to shut down for nearly an hour, spokeswoman Julie Rodriguez said. All planes were grounded between 8 p.m. and 8:45 p.m., and some flights were diverted to Tucson and California for landing. At least two flights were canceled.
The storm was so powerful, it blew a heavy cloud of dust into the terminals, triggering fire alarms. Airport custodial crews were busy washing windows and cleaning curbs late Wednesday morning.
Phoenix Fire Department received more than 700 calls for service as the storm rolled through the city.
"We expect that," said Capt. Scott Walker, a spokesman for the Fire Department. "When storms come to the area ... we have procedures in place."
The storm also caused power failures in some areas. In Tempe, officers were directing traffic at intersections in blackout areas, police Lt. Scott Smith said. Significant outages were also reported in Apache Junction.
Salt River Project reported 9,400 customers across the Valley lost power during the peak of the storm.
Arizona Public Service reported that the entire town of Quartzsite lost power, affecting 2,000 people, and blackouts affected 6,000 customers in Buckeye.
Significant outages were also reported in Apache Junction, central and south Phoenix, and south Scottsdale. APS reported Wednesday morning that 600 customers in the far West Valley were still without power, but outages should be fixed by the end of the day.
A semitruck was blown over along Interstate 8 near milepost 169, 6 miles southwest of Casa Grande, Ellis said. Twenty power poles went down, and a tree fell on a police station near Sacaton in Pinal County.
The storm brought down live wires in Tempe, and one started a fire near Rural Road and Southern Avenue, Smith said. The blaze was quickly extinguished.
In Chandler, winds toppled nine trees at the intersection of Chandler and Arizona avenues. Police officers used chainsaws and a tow truck to clear the debris.
Although the cause of the storm's speed was yet to be determined, Weather Service officials said the storm's unusual density was caused by little rainfall in affected areas during the past several months.
One lingering effect of Tuesday's storm: Hazardous air quality.
According to Arizona Department of Environmental Quality communications director Mark Shaffer, a site near downtown Phoenix measured 6,348 micrograms per cubic meter of PM10, which is a classification of fine particles in the air. Any reading during an hour that is greater than 150 micrograms of PM10 per cubic meter is considered exceeding national air quality standards for that hour.
Officials said coughing can usually rid a person's system of PM10, but too much PM10 inhalation can be dangerous for the elderly with pre-existing health conditions, children, and people with respiratory problems.
"It is very much our hope that people were inside during the peak conditions of this storm," Shaffer said.
After Tuesday night's storm, health experts were also warning people in the Valley about possible increased Valley Fever exposure. Valley Fever spores, the cause of the infection, are carried in dust.
"In general, people should avoid being outside during dust storms," said Rebecca Sunenshine, a public health physician for the Maricopa County Health Department. "People with depressed immune systems, including people on chemotherapy and those infected with HIV, are especially at risk."
Officials said that if a person needs to be outside during a dust storm, wearing a mask would be helpful in preventing Valley Fever.
Although 60 percent of people infected with Valley Fever don't exhibit any symptoms, the 40 percent that do can experience "significant interruption in their lives," Sunenshine said. On average, the symptoms of Valley Fever remain for six months and are marked by pronounced fatigue, flu-like symptoms and coughs.
Sunenshine suggests that anyone with symptoms that last longer than two weeks visit a doctor and request getting tested for Valley Fever.
Because the period of time between when a person is infected with Valley Fever and the time when the person shows symptoms fluctuates between one and four weeks, Sunenshine said she expects Valley Fever cases to increase within the next month due to the dust storm.