Snow, record heat and possible tornadoes forecast in the USA

While people stripped off their T-shirts and shorts in record-breaking temperatures across much of the continental United States on Wednesday, several inches of snow blanketed Hawaii's mountain peaks and residents of the Great Plains braced for possible tornadoes.

The US forecast for Wednesday offered a range of mild to severe weather over the Halloween weekend.

As firefighters battled wildfires in Colorado and meteorologists issued red flags of fire danger, the high elevations of Hawaii's Big Island resembled the Rocky Mountains in winter.

Several inches of snow blanketed the peaks of Mauna Loa and Mauna Kea, the highest peaks in Hawaii and part of the state's Volcanoes National Park.

“Due to winter weather conditions, the summit is currently closed to use both during the day and overnight, and permits for the Mauna Loa Summit Cabin are temporarily on hold,” Volcanoes National Park said in a statement on its Facebook page.

Meanwhile, a major storm system is expected to move into the Rocky Mountains, bringing up to a foot of snow in October. But elsewhere in Colorado, firefighters were dealing with what investigators suspect was a “human-caused” wildfire that spread to 166 acres near the town of Divide and was 80% blazed Wednesday. could be contained.

The wintry weather expected for the Rocky Mountains was offset by record-breaking temperatures in much of the country starting in Detroit, where temperatures of up to 80 degrees are expected on Wednesday. In Laredo, Texas, the temperature is expected to reach 94°, which would set a new daily record.

On Tuesday, daily temperature records were broken in Austin, Texas, where the temperature reached 90 degrees; Chicago, where the temperature rose to 82°C, setting a record; and Cleveland, Ohio, which reached 78 and also set a record.

Detroit reached a record-breaking 79 degrees on Tuesday. Green Bay, Wisconsin, reached 82 degrees Tuesday, breaking a daily record set in 1937.

Parts of the Northeast could experience the warmest Halloween on record, officials said.

In the heartland, which also saw high temperatures this week, developing severe weather could trigger some strong tornadoes from Texas to Iowa on Wednesday afternoon and into the evening hours.

The National Weather Service is also warning of an increased risk of severe thunderstorms for parts of eastern Kansas, northeast Oklahoma and northwest Missouri on Wednesday.

“Severe thunderstorms capable of producing large hail, damaging wind gusts and some tornadoes are expected this evening across the central Missouri Valley and central/southern Plains, including portions of eastern Kansas and Oklahoma into Missouri,” the NWS said in A detailed outlook was released on Wednesday.

ABC News' Max Golembo contributed to this report.