Published 8:06 PM EDT Oct 1, 2018
PHOENIX — Tropical Storm Rosa is striking fear into the heart of Arizonans who know the damage major flooding can deliver in the desert, but Valley of the Sun residents are breathing a small sigh of relief after weather reports downgraded what had been a Category 3 hurricane to a tropical storm.
People across Arizona are staying on weather watch because the storm's remnants, now expected to move into the state Tuesday morning, still are expected to pummel much of the state with heavy rains.
As of Monday morning, National Hurricane Center forecasters expect a moderate chance of flash floods in the southwest corner of the state but the entire state and beyond has some risk of flash flooding. In central and southern Arizona, 2 to 4 inches of rain is expected with some areas in the mountains receiving 6 inches; that mountain rainfall is what could be a worry.
Images and videos of darkened skies, blustering dust storms, rain and flooding across Arizona already had begun circulating on social media Sunday afternoon.
► Oct. 1: Tropical Storm Rosa brings flood threat to 12M people in Southwest
► Sept. 27: Unusually warm sea water boosted 2017's catastrophic hurricane season
► Sept. 14: Typhoon Mangkhut kills 12 in Philippines, heads to southern China
Arizona has a history of major floods.
The most recent was in 2014 when the Phoenix area was inundated with record-setting rainfall that flooded at least 200 homes in the Phoenix suburb of Mesa and turned Interstate 10 into a lake.
Sept. 8, 2014
In 2014, a massive storm fueled by the monsoon and a lingering Pacific Ocean hurricane surprised the Valley with record rainfall of up to 5.5 inches. Dozens of cars were stranded on I-10 after the freeway flooded.
When a pump system failed to kick in, a Mesa neighborhood turned into a river. More than 10,000 homes were without power, prompting then-Gov. Jan Brewer to declare a statewide emergency.
Damage and clean-up costs exceeded $18 million.
Jan. 19, 1993
The usually dry Salt River transformed into a raging, destructive waterway after multiple days of heavy rainfall.
The storm washed away shoring from the under-construction Mill Avenue Bridge in Tempe and sent tons of garbage down the river as the water reached a landfill. Eight people were killed and 112 injured, according to Arizona Republic archives.
Sept. 28 to Oct. 5, 1983
Moisture from Tropical Storm Octave dumped more than 6 inches of rain onto the Valley for five days in 1983. Fourteen people were killed in the flooding.
The Gila River overflowed its banks, forcing the closure of I-10 south of Phoenix. Stanfield and Maricopa residents climbed onto their roofs and waited for National Guard helicopters to rescue them.
The Republic previously reported the storm caused more than $500 million in damage and left 10,000 homeless.
1970 Labor Day Flood
In 1970, Arizona's deadliest flash flood killed 23 people on Labor Day.
More than 11 inches of rain pounded parts of the state over 24 hours on Sept. 7, 1970. Campers near the Mogollon Rim area weren't warned about the approaching water until it was too late.
Many of the victims were in cars, trying to outrun the water. The storm caused $5.8 million in damage.
The Great Flood of 1891
Maricopa County's largest flood occurred Feb. 19 to 26, 1891, when the Salt River swelled to 18 feet deep and 3 miles wide following days of rain, The Republic reported.
A railroad bridge over the Salt River in Tempe collapsed, destroying homes along the river bank.
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