Wildfires are rampaging across parts of the Desert Southwest and California, where an active start to the summer fire season is underway as some states in the region are seeing a spike in coronavirus cases.

Continued dry, hot and windy weather is forecast in the vicinity of the Bush Fire raging northeast of Phoenix, which nearly doubled in size Monday night into early Tuesday. As of Wednesday morning it became the seventh-largest fire in Arizona history.

Located in the Tonto National Forest, the 89,058-acre Bush Fire has forced the evacuation of a number of communities, including Tonto Basin, Punkin Center, Sunflower and Apache Lake — displacing about 2,000 residents.

Fire authorities have urged residents to evacuate immediately, noting failure to do so could mean “emergency services may not be able to assist you further.”

Jake’s Corner, home to about 1,000 residents, was put to “set” status on a three-tiered “ready, set, go” scale. That often means the people should have clothing, critical documents, prescriptions and nourishment packed and a vehicle ready to flee.

Covid complications

Already fraught evacuation decisions are even more complex this year due to the spread of the coronavirus. Arizona has been seeing a surge in cases, including in Maricopa and Gila counties, where evacuations are being ordered.

On Tuesday, Arizona hit a new high for daily new cases, reporting 2,392 positive tests. This was the 11th day this month that the state set a new case high, according to a Washington Post analysis. The number of covid-19 hospitalizations in Arizona has increased by 81 percent since Memorial Day, with 1,506 people now hospitalized. Inpatient beds across the state are at 80 percent capacity.

Maricopa County includes Phoenix and reported nearly 5,500 new cases in the past week. Gila County, where some evacuations have been ordered, has 91 cases; 43 of them have been reported in the past week.

By Wednesday morning, the flames had torched an area twice the size of Washington, D.C., and continued growing as triple-digit heat and winds gusting to 30 mph worked against firefighters. The largest fire in the nation, it was only 5 percent contained.

Fires run rampant across the Southwest

Access to the North Rim of the Grand Canyon was also closed over the weekend, and has remained shut since another blaze — the Mangum Fire — burns in the forest atop Kaibab Plateau in northern Arizona. The fire was estimated at 47,561 acres early Wednesday and was only 3 percent contained. Smoke from the blaze poured into Utah and Colorado, casting an eerie, milky haze overhead.

Additional fires continued east of Phoenix, including the Sawtooth Fire. Fire personnel gained the upper hand over that fire last week after it burned some 25,000 acres. That fire was initially sparked by lightning and exacerbated by strong winds and ample, parched vegetation.

Another lightning-initiated fire, the Bighorn Fire, first broke out along the western end of the Santa Catalina Mountains northeast of Tucson on June 5. Since then, it has surged westward, threatening communities in the Catalina Foothills. Summerhaven and areas north of Organization Ridge Road have been placed in “go” status, while places farther south, including the Lower Catalina Highway and Lower Mt. Lemmon, are being told to monitor the situation in case evacuation orders are given.Southwest Monsoon

Pima County, where the fire is burning, has had 979 covid-19 cases in the past week.

Catalina State Park was closed as a result of the fire, with a number of trails impacted as well. The fire had burned at least 17,506 acres by Wednesday morning.

Arizona’s fires are likely to continue until the Southwest Monsoon season kicks in later this summer, bringing daily doses of showers and thunderstorms to the parched landscape.

Fire activity picking up in California amid hot, dry weather

A number of wildfires have also erupted in the Central Valley of California as well as the Sierra Nevada. Those have been relatively small so far.

The Avila Fire near San Luis Obispo remained at 400 acres on Tuesday evening, and was 50 percent contained — up from the 10 percent containment reported early Tuesday. According to CalFire, four helicopters and 42 engines have been assigned to combat the blaze, which prompted evacuations earlier in the week.

Contributing to the outbreak of fires across the southwestern United States has been a persistent hot, dry air mass that has sapped moisture out of vegetation. A wave of low pressure passing through the Great Basin has sent dew points — a measure of how much moisture the air contains — plunging at the same time as winds have increased.

“This flow has scoured out most of the moisture,” wrote the National Weather Service in Tucson in an online discussion. “Beyond [Wednesday], we will continue to see dry conditions … Temperatures will jump back to around 5 to 8 degrees above average to start the new week.”

June into early July is typically peak fire season for Arizona. June is historically the driest month of the year in Phoenix — and yet July is the wettest. That stark contrast stems from the monsoon, which can abruptly begin as moist southerly winds bring life-giving downpours and thunderstorms to the arid desert landscape.

Until then, only isolated thunderstorms occasionally form. These storms often produce “dry lightning,” which occurs when hot, dry air near the ground causes rain to evaporate before it falls. This can lead to new fires. In addition, wind gusts associated with dry thunderstorms can cause fires to spread quickly.

An ominous sign for California’s fire season

The Southwest Monsoon will not help California though, where the wildfire season is just beginning. A long season looks to be ahead, with the National Weather Service’s Climate Prediction Center highlighting the odds of a warmer than average summer. Near to below average rainfall is expected, and the National Interagency Fire Center is forecasting above average fire danger for northern parts of the state during July.

California’s ongoing fires may be an ominous precursor for what’s to come. While plenty of snow fell in the Sierra Nevada Mountains this winter, it melted earlier than average, leading to dry conditions leading into the summer. The state has also seen a rare June Santa Ana wind event, which are typically associated with some of the state’s deadliest fires.

Fires caused nearly 150 fatalities in California in 2017 and 2018 combined, and on Tuesday, utility giant PG&E pleaded guilty to 84 counts of involuntary manslaughter for its role in sparking the devastating Camp Fire that wiped out Paradise, Calif., in 2018. The fire began with a spark on a downed electrical line during high winds.

There is increasing likelihood that a potent dome of high pressure — accompanied by long-duration hot and bone-dry weather — will becomes established over the West Coast late this month. That would accelerate drying of fuels and ripen the risk of dangerous fire growth later in the season.

Unlike in Arizona, there is no monsoon — fire season in California does not really “end” until the wintertime rains arrive late in the year.

Jacqueline Dupree contributed reporting.