Summer rainy season sets in in the Four Corners region

FLAGSTAFF, Ariz. – Some Arizona residents were ravaged by flooding last year as the summer rainy season, known as the monsoon, erupted on mountains scorched by flames – another concern this year for residents in the throes of a particularly ferocious wildfire season.

With the seasonal weather pattern starting Wednesday, many are concerned about flooding as wildfires devastate more of the ponderosa pine forests around Flagstaff in northern Arizona.

The monsoon can be a mixed bag—cooling sweltering cities like Las Vegas and Phoenix, but carries the risk of flooding for both mountain towns and low-lying deserts. It promises rain, but does not always deliver. And even if it does, the moisture isn’t evenly distributed across the Four Corners region and beyond.

The monsoon left the region largely parched in 2019 and 2020, but had a remarkable turnaround last year when some cities registered their wettest summers.

The outlook for this year calls for equal opportunities for below, above and normal precipitation, although that could change when new seasonal forecasts are released Thursday, climatologists said.

Conditions are already starting to set up for moisture that could move into northern Arizona and other places later this week that could help firefighters, as well as bring dry lightning that could spark more fires.


“There are a lot of useful ingredients to this,” said Brian Klimowski, chief of the National Weather Service in Flagstaff. ‘That is the relative humidity that suppresses the fire behavior and hopefully some rain. But not too much rain. We all know the threat and risk of flooding after the fire.”

Temperatures will warm up a bit Thursday and winds will come in northern Arizona, potentially triggering more active behavior in two wildfires burning on the outskirts of town before moisture gets in, he said.

Fire crews have rounded up about a third of the larger blaze, which has charred more than 35 square miles (92 square kilometers) since it started Sunday. Another wildfire in a more remote area has burned nearly 20 square kilometers without containment.

The evacuation orders were lowered on Wednesday. While the fires have calmed down somewhat and are largely moving away from homes, Coconino County officials urged residents who don’t have flood insurance to buy it now. Officials this week are testing sirens in an area prone to flooding, smashing sandbags and concrete barriers to reduce potential damage, but they won’t know the extent of the risk from the latest wildfires until the area can be surveyed.

“It’s not realistic that we can stop the flooding,” Christopher Tressler, the county’s public works director, told residents Tuesday evening.

The US monsoon is characterized by a shift in wind patterns that draw moisture in from Mexico’s tropical coast. It’s different in other parts of the world, including India, Northern Australia and Africa, where people celebrate the first rain of the season, said Joel Lisonbee, a climatologist and drought information coordinator with the National Oceanic and Atmospheric Administration.

In Arizona, about half of the rain that falls during the year falls during monsoons, state climatologist Erinanne Saffell said. Still, the US Southwest is leaning toward warmer, drier weather due to climate change.

Those conditions, along with strong winds, led to a busy wildfire season in the western US this spring. In all, federal officials say more than three dozen major fires have burned more than 1,875 square miles (4,856 square kilometers). More than 6,700 wildfire fighters and support personnel are deployed in incidents across the country.

New Mexico has the largest wildfire in the US, one that has scorched more than 1,354 square miles and another that is marching through another corner of the state.

The weather service warned this week of a potential critical fire hazard in the South Park region and the eastern plains of Colorado. Some local governments banned outdoor fires on Wednesday.

A 500-square-mile wildfire in southwest Alaska is sweeping through dry grass and scrub in the largely treeless tundra away from an Alaskan village. A front expected to move in Thursday will bring southeast winds that will lessen the threat to St. Mary’s.

Temperatures were high in inland California on Wednesday, but incoming low pressure was expected to cool things down and create a chance of mountain and thunderstorms in the north by the weekend. Forecasters noted a chance of local fires in the eastern Sierra Nevada due to drought and gusts from the approaching system.

Associated Press writers John Antczak in Los Angeles; Susan Montoya Bryan in Albuquerque, New Mexico; Mark Thiessen in Anchorage, Alaska; and Jim Anderson in Denver contributed to this report.