An MTA employee tries to help commuters in the Times Square station, after an early morning deluge drenched New York City's subway system halting or limiting service on many lines on Aug. 8, 2007. View Full Caption Flickr/swerz

NEW YORK CITY — Just before 6 a.m. on Wednesday, Aug. 8, 2007, a storm barreled through New York City, dumping up to 4 inches of rain within two hours amid tornado-force winds. It completely crippled the subways in a way unfamiliar to riders at the time.

It was the third storm that year to set off flooding across the subway system — including an April 15 event that dumped the most rain across the city since 1882, according to an MTA storm report.

But the August 8 weather system was the most severe because the fast and furious rainfall knocked out every line at the height of the morning rush, leaving the city’s subway system crippled for up to eight hours.

It forced the MTA to re-evaluate how it handles emergencies, particularly with the threat of climate change potentially bringing more severe weather to the city. And without the changes made after August 8, 2007, Hurricane Sandy's damage in 2012 could have been even worse.

Elliot Sander, the president of NYC Transit at the time, was on the Jackie Robinson Parkway on his way to a site visit when the storm hit.

“It started raining really hard, which was not predicted,” he told DNAinfo New York. It was just after 7 a.m. when he started receiving notification of flooding at various stations, coming in at a rate of one every three minutes, an MTA report found.

“And then all of a sudden the system just started shutting down,” recalled Sander, who left the MTA in 2009 and is now managing director of transportation at Hatch USA, an engineering and consulting firm.

The storm dumped between 1.4 and 3.5 inches over two hours on most of the city, with the Owl's Head wastewater treatment plant in Bay Ridge recording a whopping 4 inches of rain. Dozens of homes in Brooklyn were damaged by the tornado.

Floodwaters reached the platform at the Bayside LIRR station and inundated E and F train stations in Queens.

A month later, President George W. Bush declared Brooklyn and Queens eligible for federal disaster assistance following the two-hour storm.

In the 10 years since, the MTA has worked on its its storm preparedness and has overhauled everything from its weather forecasting to its ability to shut down the subway system.

The changes have helped the agency prepare for larger, more devastating storms such as Hurricane Sandy — which caused approximately $5 billion in damages to subways, rail yards, tunnels and more.

"What needed to occur is we needed to ensure the MTA was able to respond in a coordinated fashion, system-wide, to an event of this nature," Sander said. "We put in an emergency protocol that is quite helpful in responding to emergencies like that."

By 2009, the agency had spent around $30 million in significant flood-mitigation efforts.

A spokesman from the MTA declined to comment for this story.

Here are some of the most significant changes implemented after the storm, which has helped as the MTA recover from storms including Hurricane Sandy.

► Use of multiple weather forecasters to better prepare for storms

At the time, the agencies within the MTA used different weather-forecasting services. The report released a month after the storm found that none of these services provided enough warning.

As a result of the storm, the agency began using a shared weather-forecasting service, installed Doppler radar screens in its agency operation centers and also opened a new emergency-response room.

► Improve drainage of water and debris

The intense rainfall quickly washed debris into drains, not allowing for normal drainage to take place, the report found.

There were 26 serious flooding incidents, with four train lines taken out of service for more than eight hours, the MTA found.

Four stations that were the most prone to flooding — including the 65th and 36th street R and M stations in Queens, the Parsons Boulevard F train station in Queens, and 79th Street 1 train station in Manhattan — experienced serious flooding from water overflowing from the streets and sidewalks, according to the MTA

More than a dozen other stations had some flooding from rainwater overflowing from the street. The Times Square station, the 110th St. 2/3 train station and the 23rd Street 6 train station flooded with back flow from sewers.

Seven other stations that didn’t experience serious flood had either recently been "jett-cleaned," had temporary pumps installed, or had properly maintained sewer lines, according to the MTA.

Within a year of the storm, the MTA installed drainage grates at flood-prone locations across the city. The agency has continued work to clear debris from the track, including efforts like last year's "Operation Track Sweep," which set out to clean every station and track in the city.

► Prepare for full shutdown of subway system — and prepare for climate change

After the epic meltdown of the subway system, the MTA began looking into the possibility of shutting the subway, rail and bus systems down ahead of major weather events. Officials shut the subway down for a 1992 nor'easter, but did not implement it again until Hurricane Irene in August 2011.

It was closed again before Hurricane Sandy and for the 2015 blizzard.

The biggest takeaway from the storm, though, was the realization that these severe weather patterns could be more common, Sander said.

"The MTA needs to, on a regular basis, update its assessment of the system as climate change appears to continue to have the impact that it has," he said.

"The transit industry overall and the MTA for its part needs to continue to keep its eye on the sudden impact of climate change."