Wildfires are growing across the western US, triggering evacuation orders, as the threat of dry lightning prompted red flag warnings and fire weather watches to be issued from central California to northwest South Dakota on Monday.

Iran PressAmerica: As temperatures again rise, 80 large wildfires were burning across nearly 1.2 million acres in the West Sunday — 10 more than the previous day, according to the National Interagency Fire Center. These include 18 in Montana, 17 in Idaho, and nine each in California and Oregon — where the largest blaze in the US, the Bootleg Fire, grew even bigger to raze land about the size of Los Angeles Sunday. The explosion of wildfires comes as another heatwave grips the country, this time with the intensity focused on the northwest and northern areas.

Many of the wildfires started amid an unprecedented heatwave that scientists say was driven by human-caused climate change.

US Forest Service Operations Section Chief Jake Cagle noted that 100,000-acre wildfires are no longer rare events in California, "which experienced a record wildfire season in 2020 and is already outpacing those numbers this year," the Los Angeles Times reported Sunday night." Multiple weather hazards are affecting the West and these threats will likely continue much of this week," the US National Weather Service warned.

"Elevated and critical fire weather conditions and isolated dry thunderstorms will be widespread," from California to Montana, where "excessive heat will persist through mid to late week," the USNWS added.

A red flag warning was in effect for southern Oregon areas affected by the Bootleg Fire — which has scorched 476 square miles and was about 22% contained as of Sunday afternoon, per InciWeb.

A red flag warning was in effect across the Northern Rockies, a region now engulfed in a heatwave that threatens to spark new fires. Several communities were under evacuation orders from California's Tamarack Fire, south of Lake Tahoe near the Nevada border was burning uncontained across 18,299 acres near the town of Markleeville, according to a statement from Humboldt Toiyabe National Forest.

In Wallowa County, Oregon, the Elbow Creek Fire that erupted Thursday and has forced several communities to evacuate had burned across nearly 11,000 acres and was 10% contained Sunday, according to KATU.

A wildfire in the mountains of northeast Oregon swelled over 17 square miles Sunday, AP notes.

The Sugar Fire in Plumas County, one of two blazes ignited by lightning that make up the Beckwourth Complex fires, California's first 100,000-acre wildfire this year, had razed over 105,000 acres was 82% contained Sunday night, per the LA Times.