Dangerous flooding may unfold in southwestern US as Newton threatens 2 months' worth of rain in hours

By Andy Mussoline for AccuWeather

Significant flooding may develop across the southwestern United States through Wednesday as Newton fuels soaking rain across the region.

Newton slammed into Baja California as a Category 1 hurricane early Tuesday morning. Despite weakening, the system will send a surge of torrential rain into the Southwest through Wednesday night.

An organized swath of heavy, flooding rainfall will move across southeastern Arizona Wednesday. Phoenix will be located along the northwest periphery of the heavy rain, as the core of the steady rain will target areas farther east across southeastern Arizona, including Tucson.

More from AccuWeather: Southwest US interactive radar

One to 3 inches of rain can accumulate in less than 24 hours, and in a few cases, only a matter of hours. This amount of rain is something that typically accumulates over the course of one or two months in many Southwest locations during the late summer.

"Tucson averages just 1.29 inches of rain during the month of September, and some areas in and around Tucson could get that much rain in just one day," said AccuWeather Meteorologist Brian Thompson.

Related: 15 of the deadliest American hurricanes ever

15 of the deadliest American hurricanes ever
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15 of the deadliest American hurricanes ever

Hurricane Hugo, 1989: 21 deaths

Hurricane Hugo made landfall as a Category 4 storm in South Carolina. It caused 21 deaths in the US and resulted in $7.1 billion of damage. At the time, it was the costliest storm in US history.

Photo courtesy: Getty

Tropical Storm Allison, 2001: 41 deaths

While not an official hurricane, Allison clocks in as the costliest and deadliest tropical storm in US history, causing 41 deaths and costing more than $5 billion in damage. The storm started over the Gulf of Mexico near Texas, then traveled east, causing floods like the one pictured here in Houston, Texas.

Photo courtesy: NOAA

Hurricane Irene, 2011: 56 deaths

Hurricane Irene, the first storm to hit the US since Ike three years earlier, made landfall in North Carolina as a Category 1 storm. The storm eventually made its way up to New York City, bringing flooding -- like the kind pictured here in Puerto Rico -- and causing $7.3 billion in damage overall.

Photo courtesy: AP

Hurricane Floyd, 1999: 57 deaths

Hurricane Floyd was a catastrophic storm because of the rain it brought along. The rain caused extreme flooding from North Carolina on up as the Category 2 storm traveled up the East Coast.

Photo courtesy: NOAA

Great Atlantic Hurricane, 1944: 64 deaths

The Great Atlantic Hurricane of 1944 was also devastating to New England, with 64 deaths and more than $100 million in damage. The storm was a Category 3 as it sped up the coast, hitting the Carolinas, Rhode Island, and Long Island before downgrading to a Category 2 in Maine.

Photo courtesy: NOAA

Hurricane Agnes, 1972: 122 deaths

Hurricane Agnes, as seen in this image made it all the way inland to Pennsylvania. Although it was only a Category 1 storm (with winds from 74-95 mph), it still caused 122 deaths and caused $2.1 billion in damage.

Photo courtesy: NOAA

Hurricane Ike, 2008: 195 deaths

The third costliest storm in US history, with $29.5 billion in damage, occurred in September 2008. Starting off the west coast of Africa, Hurricane Ike made its way over the Caribbean and into the Gulf, making US landfall in Texas as a Category 2 storm

Photo courtesy: Reuters

Hurricane Camille, 1969: 256 deaths

Hurricane Camille formed in the Gulf of Mexico and hit Mississippi as a Category 5 storm. Camille caused more than 256 deaths and clocks in as the second most intense hurricane to hit the US.

Photo courtesy: NOAA

New England, 1938: 256 deaths

Nicknamed "Long Island Express," the storm hit Puerto Rico as a Category 5 storm before charging north and hitting Long Island, New York and Connecticut as a Category 3 hurricane. The storm was responsible for more than 256 deaths.

Photo courtesy: NOAA

Hurricane Sandy, 2012: 285 deaths

With $71.4 billion in damage, Hurricane Sandy was the second costliest hurricane in US history. The Category 1 storm pummeled New York City, flooding the city's transportation systems and leaving thousands of homes destroyed.

It's looking more and more like Hurricane Joaquin won't make landfall in the US and join the list of most horrific storms in US history.

Photo courtesy: AP

Hurricane Audrey, 1957: 416 deaths

The U.S. started naming storms with women's names starting in 1953. Hurricane Audrey, the first storm of the 1957 hurricane season was the deadliest of the 1950s. It originated in the Gulf of Mexico, making landfall in Texas as a Category 4 storm. This image of the storm shows just how far hurricane imaging has come.

Photo courtesy: NOAA

Atlantic-Gulf, 1919: 600 to 900 deaths

This Category 4 storm swept into the Gulf of Mexico right under Key West, Florida(pictured), landing as a Category 3 storm in Corpus Christi, Texas. Anywhere from 600 to 900 people died in that storm.

Hurricane Katrina, 2005: 1,200 deaths

Hurricane Katrina is arguably the most notorious storm of the 21st century. The storm made landfall as a Category 5 near Miami before striking Louisiana as a Category 3 storm. Katrina was the third deadliest, and costliest hurricane in U.S. history with more than 1,200 deaths and $108 billion in damage.

Photo courtesy: Reuters

San Felipe Okeechobee, 1928: 2,500 deaths

This hurricane was the second deadliest in US history, with more than 2,500 deaths. The Category 4 storm made landfall in Palm Beach on September 10, 1928. Puerto Rico got hit hard as well, with winds at 144 mph.

Photo courtesy: NOAA

Galveston, Texas in 1900: 8,000 to 12,000 deaths

The deadliest hurricane in US history happened at the turn of the 20th century. The Category 4 of 5 hurricane -- with winds anywhere from 130-156 mph -- made landfall in Galveston, Texas (pictured), then headed north through the Great Plains. Anywhere from 8,000 to 12,000 people died in the storm.

Photo courtesy: Creative Commons


The excessive rainfall can quickly flood streets and prompt rockslides in the more mountainous terrain, both of which can lead to road closures.

In addition to street hazards, typically dry stream beds and drainage areas can become quickly inundated with water.

More from AccuWeather: Severe Weather Map: US watches and warnings

"Streams, rivers and drainage areas can flood quickly with these tropical downpours, so be prepared for rapidly changing conditions into Wednesday night," said Thompson.

Hikers in the region should be aware of these dry stream beds and drainage areas as they can quickly turn into raging rivers.

The heaviest rain will taper off across Arizona Wednesday night as it shifts eastward into New Mexico.

More from AccuWeather: Phoenix MinuteCast®

Although similar threats will continue in New Mexico, flooding incidents will become more localized since the intensity of the rain is expected to diminish.

Gallup and Truth or Consequences, New Mexico, will be among the cities at risk for flooding rainfall Wednesday night. Rain, some heavy, will move into Albuquerque, New Mexico, but the overall risk for flooding is rather low.

The rain will move out as quickly as it came in. A period of drier and warmer weather will then quickly follow Thursday and Friday across the region as sunshine prevails, allowing for cleanup in flooded areas.

Leftover moisture from Newton will help fuel drenching rain and thunderstorms across the Plains and Midwest late week.

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