New Jersey remains under a state of emergency Tuesday after flash flooding devastated many communities Monday night, especially in Union and Somerset counties. 

Gov. Phil Murphy toured some of the damage Tuesday morning in Berkeley Heights.

"Last night, we got crushed," he said. 

Murphy spoke about two deaths in the city of Plainfield and about a home explosion in the borough of North Plainfield. 

"We're seeing more of this, more frequent and more intensity," he said. "Six inches of rain in under two and a half hours, in two waves -- one wave, knocked a lot of these communities a little bit off kilter; the second one just came in for the kill. So we're assessing around all these communities and counties."

The governor said he was in touch with the White House, and he warned more unsettled weather may be on the way. 

"We're in one of these patterns right now, hot and humid, late afternoon-early evening thunderstorms," he said. "It doesn't feel, as I stand here now, as though tonight, tomorrow, Thursday will be at the same level of intensity that we saw last night, but you never say never." 

Berkeley Heights Mayor Angie Devanney joined Murphy for the briefing and said that she experienced some flooding in her garage. 

"I've seen water gushing out of the roadways, I've never experienced that, almost like a geyser, large boulders that have rolled down Mountain Avenue," she said. 

Police in Plainfield confirmed two people were killed when a vehicle was swept into Cedar Brook during the storm. Their names have not been released. 

"They were in a submerged automobile, and their remains were extracted at some point overnight or first thing this morning," Murphy said. 

Earlier this month, two other people in the city were killed when a fast-moving storm whipped through. That system also killed a woman in North Plainfield. 

"All of Plainfield grieves this latest loss," Plainfield Mayor Adrian O'Mapp said in a statement Tuesday. "To lose four residents in such a short span of time is unimaginable. We mourn with the families, and we remain committed to doing all we can to strengthen our emergency response systems and protect residents from future harms."  

It was a chaotic night across Union County. As first responders were busy with dozens of water rescues and shutting down roads, they received a report of a house explosion in North Plainfield.

Firefighters arrived to find a home on Parkview Avenue splintered into pieces and engulfed in flames. The force of the explosion was so powerful, the debris ended up halfway down the block. 

After getting the fire under control, they did a thorough search and determined the house was unoccupied.  

The explosion happened shortly after 11 p.m. as the floodwaters receded, according to neighbors. The cause remains under investigation. 

"Everybody came out, me and my neighbors were just standing out here, trying to have as normal of a conversation as you can about this. And then, mid-conversation, the house just went up, the roof blew off," one neighbor said. 

"It was such a huge noise," another neighbor added. "The force of the water was moving the cars, so I thought maybe it was just two cars that collided."   

Torrential rains complicated the firefighting effort, and first responders were seen wading through ankle deep water as they dragged their hose lines. 

Meanwhile, water raced into other homes on the block through basement windows and bathroom plumbing. 

"This is what gets me and I feel sad, because I had so many bins of my kids' drawings and paintings from they were in elementary school, that now I think I've completely lost most of it," said one woman. "We're here, we're safe, the most important part is that we're safe." 

Union and Somerset counties reported some of the highest rainfall totals. Watchung saw 6.51 inches while Mountainside saw 5.34 inches.

Several drivers had to be rescued Monday night as cars stalled across the Garden State and in parts of New York. 

Many of the rescues were reported in Scotch Plains, where a bus, ambulance and UPS truck were all seen struggling in the high water. Crews used rafts and a frontloader to reach people after the intense rainfall caused the Green Brook River in the Watchung Reserve to overflow and spill onto Route 22. 

Roselle Park Mayor Joseph Signorello III said the storm was unlike anything he's seen in his seven years as mayor.

"Something so sudden -- just to set context, Hurricane Ida was about 10 inches in over a three hour-four hour timeframe. This was about 7 inches, so you're talking about 70% of the rain that we saw in Hurricane Ida," he told CBS News New York. 

He said businesses there have been hit before, and it's becoming more common and more intense.

"We are, as a municipality and regionwide, trying to adapt. We keep our sewers clean, we try to expand our sewers where we can. But at the end of the day, these natural disasters are something like we haven't seen and we're going to continue to see, and we need to make ourselves more resilient," he said. 

Middlesex, Morris and Somerset counties remained under a flood warning until 7:15 a.m. Tuesday, and Route 22 eastbound was still closed in Somerset County for the morning commute.