‘Bomb cyclone’ hits Boston: Severe flooding, 20k without power across Massachusetts (VIDEO, PHOTOS)

Icy flooding and heavy snowfall have struck Boston as whiteout conditions and gusty winds follow high tides on the New England coast, battering the region. More than 20,000 residents have been left without power.

The storm, dubbed a “bomb cyclone,” touched down in the Northeast, particularly in Boston, where conditions continued to worsen Thursday as the storm settled in.

Coastal Massachusetts faced major flooding, as over a foot of icy water filled roadways about seven miles northeast of downtown Boston, according to ABC News.

The NWS said the worst of the coastal flooding is over, but warned the water would be slow to drain, and added that some of it would likely freeze as temperatures drop heading into the weekend.

READ MORE: Ice-cold iguanas plunge from Florida trees during winter storm cold snap (PHOTOS)

All schools will be closed in Boston Friday, and shelters will open in case flooding continues and evacuations are deemed necessary, Boston Mayor Marty Walsh said during a news conference, ABC News reported.

Even though the worst is apparently over, Walsh added that the flooding is still affecting parts of Boston including Seaport, Charlestown, the North End, East Boston and Dorchester.

The Massachusetts Bay Transportation Authority announced on Twitter that Boston’s ferry service has been suspended due to "severe weather and ice" in Boston Harbor.

The high tides that caused the flooding Thursday, which also affected Maine and New Hampshire, were attributed to the phase of the moon which was just past full. The level of high tide fluctuates every 12 hours, and every month there are a few high tides that are considered the highest in the cycle. Thursday's storm coincided with those high tides, according to WBUR.

Also, although the storm was around 100 miles off the coast of Nantucket, it had very strong onshore winds blowing the water toward the coastline. The quick intensification generated a lot of wind, which pushed the water toward the shore. After big waves were added to the mix, more water rushed to the shoreline which caused the flooding, WBUR reported.

On Thursday afternoon, wind gusts were said to be coming in at 60-70 mph in Eastern Massachusetts, according to the NWS.

Gusts up to 30-50 miles per hour in eastern Massachusetts are expected to last from Thursday night into Saturday, according to the Boston Globe.

By the time the storm subsides, 12 to 16 inches of snow is expected to fall in the eastern Massachusetts area, WCVB reported.

A flash freeze is also a concern in the Cape Cod region, as well as in the southeast coastal area of Plymouth County in Massachusetts, the National Weather Service said.

Thundersnow, which is a thunderstorm that occurs when it is snowing, has been reported in parts of Rhode Island and Massachusetts, according to Boston.com

READ MORE: Extraordinary storm systems visible in ‘bomb’ cyclone’s eye (VIDEO)

And throughout the East Coast, as New York, Connecticut and New Jersey also bear the brunt of the fierce winter storm, 4,000 flights were cancelled in the entire region Thursday, according to USA Today.

As the storm begins to severely affect the East Coast, it is threatening to dump as much as 18 inches of snow all the way from the Carolinas, to Maine, CBS News reported.

The NWS tweeted Thursday that the coastal flooding that has wreaked havoc on New England is getting close to levels seen during the historic Boston blizzard of 1978.

The 1978 blizzard destroyed hundreds of homes and flooded the coast. It caused $500 million in damage in Massachusetts, while also leaving 73 people dead and 4,324 injured, according to the National Oceanic and Atmospheric Administration (NOAA), WBUR reported.