• Hurricane Delta has rapidly intensified and is now an "extremely dangerous" Category 4 hurricane with winds of 140 mph.
  • It's expected to make landfall in Mexico on Wednesday, then approach Louisiana on Friday.
  • Delta is the 25th named storm of the 2020 Atlantic hurricane season, which is on track to break the record for the highest number of named storms.
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Hurricane Delta is rapidly gaining strength and has become an "extremely dangerous" hurricane — the term for storms Category 4 or higher — as it churns towards Mexico and the US Gulf Coast.

Delta is projected to hit Mexico's Yucatan Peninsula on Wednesday as a Category 4 hurricane. Its winds are expected to slow as it moves over land, but then re-strengthen as the storm heads back into the warm waters of the Gulf. Delta is then forecast to approach Louisiana on Friday.

If it makes landfall there, it will be the 10th named cyclone to hit the mainland US in a single season – breaking the previous record of nine storms in 1916. 

"There is a significant risk of dangerous storm surge, wind, and rainfall hazards along the coast from Louisiana to the western Florida Panhandle beginning Thursday night or Friday," the NHC said.

The hurricane is currently heading northwest at 16 mph. Heavy rainfall is expected over portions of the Cayman Islands, western Cuba, and the northern Yucatan Peninsula through the first half of this week, with the potential for "significant flash flooding and mudslides," the National Hurricane Center said on Tuesday morning. A hurricane warning is in effect from Tulum to Dzilam on the peninsula's eastern tip, as well as for Cozumel. 

Hurricane Delta gains strength early Tuesday, October 6, 2020.
CIRA/RAMMB

Delta emerged as a tropical depression on Sunday evening, with wind speeds of 35 mph, before quickly growing to a hurricane with 80-mph winds by Monday evening — a process called rapid intensification. Its maximum sustained wind speeds are now 140 mph. 

NWS/NOAA

So far this year, the Atlantic Ocean has produced 25 named storms in just six months. That's just three fewer than in 2005, which had the greatest number of named storms in history. But 2020 is ahead of that record-making 2005 season by more than a month, so is likely to pass it. 

The NHC exhausted its planned list of alphabetical names in mid-September, after Tropical Storm Wilfred formed in the eastern Atlantic. (Storm names go in alphabetical order but skip the letters Q, U, X, Y, and Z.) Now, it's onto the Greek alphabet – with Delta, it's already four letters in. The 2005 season made it to Zeta, which is two names away.

The latest in a destructive hurricane season

The US Gulf Coast has already experienced several destructive storms this year. Hurricane Hanna flooded streets and caused nearly 60,000 power outages in Texas in late July. Laura killed at least 17 people in Louisiana and Texas in August and caused at least $10 billion worth of damage. And Hurricane Sally killed four and caused extensive damage in Florida and Alabama in September.

A street is strewn with debris and downed power lines after Hurricane Laura passed through the area on August 27, 2020 in Lake Charles, Louisiana.
Joe Raedle/Getty Images

The National Oceanic and Atmospheric Administration predicted that 2020's hurricane season would be "extremely active," with 19 to 25 named storms — the first time in NOAA's history the forecast was that high. 

"This is one of the most active seasonal forecasts that NOAA has produced in its 22-year history of hurricane outlooks," US Secretary of Commerce Wilbur Ross said in an August press release. "We encourage all Americans to do their part by getting prepared, remaining vigilant, and being ready to take action when necessary." 

The NOAA forecast predicted there'd be seven to 11 hurricanes this season, with three to six of those reaching Category 3 or higher (that's considered "major"). So far, 2020 has seen nine Atlantic hurricanes, three of them becoming major.

An average season sees roughly six hurricanes, with three becoming major. But the Atlantic Ocean has been producing highly active hurricane seasons since 1995, according to NOAA.

Climate change makes hurricanes more frequent and destructive

Hurricane Laura decimated a neighborhood outside Lake Charles, Louisiana, when it thundered ashore as a Category 4 storm.
STRINGER/AFP via Getty Images

Storms are getting stronger on average as climate change causes ocean and air temperatures to climb — 2019 was the second-hottest year on record, and it closed the hottest decade ever recorded.

Hurricanes feed on warm water, and higher water temperatures also lead to sea-level rise, which increases the risk of flooding. Warmer air, meanwhile, holds more atmospheric water vapor, which helps tropical storms strengthen and unleash more precipitation.

Overall, the chances of any tropical cyclone becoming a major hurricane are increasing: Each new decade over the last 40 years had brought an 8% increase in the chance that a storm will turn into a major hurricane.

"We have a significantly building body of evidence that these storms have already changed in very substantial ways, and all of them are dangerous," James Kossin, an atmospheric scientist at NOAA, told The Washington Post.

Residents look through debris after hurricane Dorian hit the Grand Bahama Island in the Bahamas, September 4, 2019.
Joe Skipper/Reuters

A 2013 study, meanwhile, found that for each degree the planet warmed over the previous 40 years, the proportion of Category 4 and 5 storms increased by 25% to 30%.

"Almost all of the damage and mortality caused by hurricanes is done by major hurricanes," Kossin told CNN. "Increasing the likelihood of having a major hurricane will certainly increase this risk."

Storms are also getting more sluggish. Over the past 70 years or so, hurricanes and tropical storms have slowed about 10% on average, according to a 2018 study. That gives a hurricane more time to do damage in a given area.

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