(CNN) -- Mother Nature showed her extremes across the United States on Tuesday, with another day of dangerously hot temperatures broiling the Southwest while parts of the Northeast grapple with flooding from torrential storms.
Temperatures across much of the West will soar 10 to 20 degrees above average on Tuesday, the National Weather Service said. Forecasters issued excessive heat warnings for large swaths of California, Nevada and Arizona through the Fourth of July.
By noon, the mercury had hit 98 degrees at Reno, Nevada; 109 at Las Vegas; 104 at Yuma, Arizona; and 118 in Furnace Creek, California, in Death Valley -- where the heat was so intense over the weekend that it melted shoes. Triple-digit forecasts were posted as far north as Spokane, Washington, and the Idaho panhandle.
"Many of the same locations that broke records recently could shatter records again on Tuesday," the weather service said.
That's dreadful news for much of California, Nevada and Arizona, states that have all seen temperatures top 120 degrees in the past few days.
Forecasters in Las Vegas noted that a similar heat wave in 2005 killed 17 people. They urged neighbors and relatives to check on those most susceptible to heat-related illness -- children, the elderly and the chronically ill.
"This is a life-threatening heat event for those at risk," the advisory warned.
"Not only do they get (from) the cooling station the benefit of the water that we put out, but they can also take showers, if they need to, in here for free," Andre Ingram of the Salvation Army said. He said anyone who comes in can get as much ice-cold water as they need, when "normally they walk around just looking for it."
The extreme heat is hindering efforts to stop Arizona's Yarnell Hill wildfire, which has scorched more than 8,400 acres -- about 13 square miles of land.
The fire killed 19 members of an elite firefighting squad on Sunday when fierce, erratic winds whipped the fire in different directions. Parched land from Arizona's drought is also fueling the fire.
East Coast deluged by rain
Much of Arizona would love to get more rain. But residents on the East Coast are seeing too much of a good thing.
Showers and storms will stretch from Florida to New England through Thursday, dampening the Independence Day holiday, the National Weather Service said.
That's on top of the rainfall that quickly flooded parts of New Jersey on Monday and stranded motorists in Paramus.
"I didn't think that was going to happen, but it was up to my knee when I got out of my car," Caroline McCourt told CNN affiliate WABC.
Thunderstorms also produced three small tornadoes in Connecticut and New Jersey on Monday, but there were no reported injuries, the weather service and local authorities said.
An EF-1 twister with a top estimated wind speed of 86 mph skipped across 2.5 miles of Windsor and East Windsor, Connecticut, knocking down trees and blowing out electrical transformers there, Windsor Locks Police Capt. Chester Degray said.
An EF-0 -- which packs winds between 65 mph and 85 mph -- touched down in Greenwich, Connecticut, about 35 miles north of New York, inflicting similar damage, the weather service said. Another EF-0 went through Berkeley Heights, New Providence and Summit, New Jersey, about 15 miles west of Newark.
Drivers in Durham, North Carolina, also had to push their cars out of floodwaters on Monday. And the flooding could get worse -- cities from Georgia to New England could see 2 to 3 more inches of rain in the next few days.
CNN's Matt Smith, Lawrence Crook, Morgan Winsor, Dan Simon and Ivan Cabrera contributed to this report.