Thursday afternoon saw some of the highest tides parts of Massachusetts, New Hampshire and Maine have seen since the Blizzard of 1978, which occurred Feb. 6 and 7 of that year.
A combination of factors was behind the excessive tides.
First, there were astronomically high tides caused by the moon, which is just past full, and the storm itself. The level of high tide fluctuates every 12 hours, and each month there are a few high tides that are the highest in the cycle.
Today's storm coincided with those high tides.
The storm, although it was about 100 miles off Nantucket, had very strong onshore winds blowing the water toward the coastline. The rapid intensification created a lot of wind, which blows the water toward the shore. Add in some big waves, and you have additional water heading for the shoreline.
Finally, there has been a rise in sea level over the past 100 years.
While this rise is slow, the combination of a very high monthly tide, a big storm and sea levels a bit higher likely all contributed to battering the coastline with one of the highest tides since the Blizzard of 1978 nearly 40 years ago.