Scorching temperatures and desperately dry conditions set the stage for the rapid spread of several explosive wildfires that erupted over the weekend, forcing evacuations in California and Arizona. The blazes are a foreboding sign of what officials are warning will be another intense fire season across the American west. The so-called Pipeline fire, burning to the north of Flagstaff, Arizona, grew to an estimated 5,000 acres (2,000 hectares) after igniting on Sunday, fueled by gusty winds through the desiccated grasses and brush. The windy, warm conditions complicated containment efforts, according to officials, who added that the fire continues to be active on all sides. “Strong winds coupled with warm weather have been the challenging factor for firefighters and air resources, as winds are predicted to be 40 to 50 mph today” Coconino county officials said in an update Monday. The cause of the blaze is still under investigation and there have not been any destroyed structures, but a 57-year-old man has been arrested, Forest Service law enforcement said. Nearby, a separate blaze, named the Haywire fire, ignited early Monday morning – likely due to flying embers – and within hours had blackened more than 1,600 acres (650 hectares). The two fires are expected to combine, and are burning near where the Tunnel fire was recently contained in Coconino county. The fires have forced many residents in the Flagstaff area to evacuate for a second time this season. “Here we go again,” said resident Euelda King said as she waited with her family in a parking lot, watching smoke billow through the air and aircraft flying overhead. She said she barely has had time to settle back in after the last evacuation earlier this spring. Her family of 11 is planning to stay at the Navajo Nation casino, which is offering assistance to tribal members who evacuated. “The winds are high, and I think they’re going to have a little bit of a battle with it,” she added of the fire forming large ominous plumes on the horizon. Gusts were sweeping the smoke through Schultz Pass toward Doney Park and authorities asked everyone in the area to leave immediately. “With this thing going as fast as it is, it could get much closer, of course hoping it doesn’t,” King said. Authorities said 13 engines, nine crews, six prevention patrol units, three bulldozers and one water tender were involved in fighting the fire. An Incident Management Team is scheduled to arrive Monday. Meanwhile, in California, evacuation orders were in place Monday for remote homes near a wildfire that flared up over the weekend in mountains north-east of Los Angeles, authorities said. The Sheep Fire, which grew to more than 990 acres (400 hectares), was 18% contained as of Monday afternoon, according to officials, who also said 300 people had been evacuated from the area. The blaze broke out Saturday not far from Wrightwood near the Pacific Crest trail in the San Gabriel mountains, and moved quickly through the steep terrain covered in parched pine trees and dry brush, officials with the San Bernardino county fire department said. “Fuel moistures are low as they have been year after year,” said Alison Hesterly, a public information officer with Cal Fire San Bernardino, adding that erratic winds have shifted the flames in different directions. The landscapes were also primed to burn after going decades without fire. “A good portion of the fire area has not burned in well over 20 years,” Hesterly said, adding that some parts haven’t seen flames in more than 50 years. “They are very susceptible to the fire conditions.” The fire hasn’t yet destroyed homes but roughly 50 structures stand in its path. “We haven’t had fires running through the homes,” Hesterly said, “but those homes are definitely threatened.” The fire erupted just days after local, state, and federal officials gathered in Los Angeles to share concerns about the elevated risks and extreme conditions that are only expected to worsen as the weather warms and the drought deepens in the coming months. Roughly 60% of California is categorized in extreme drought by the US drought monitor and moisture levels in vegetation across the state are abysmally low. Officials said the conditions are 40% drier than they were at this time of year in 2016 – one of the driest years on record in the region. “We’re getting hotter, drier, faster,” said Dustin Gardner, chief of the Ventura county fire department, noting that the last few years have intensified into an alarming trend. The climate crisis, which has produced hotter temperatures and accelerated drought conditions, has elongated fire season and contributed to extreme fire behavior that makes blazes harder to battle. Nearly 2.5m acres (1m hectares) have already burned across the US this year, far more than double the amount for last year at this time and more than 128% above the 10-year average, according to the National Interagency Fire Center. In preparation for an expected escalation in fire conditions, the agency has also elevated its preparedness to level 2, signifying that “several geographic areas are experiencing high to extreme fire danger”. The south-west, which has been hammered by blazes early in the season, is forecast to have a robust monsoon season that will offer some reprieve after the June onslaught, but until the rains come, the region remains at high-risk. California and the Pacific north-west, however, will face significant fire potential through the end of the summer.