1776 Battle of Long Island
The Fog at the Battle of Long Island
(Brooklyn Heights Evacuation, August 1776)
After a devastating defeat on Long Island, Washington's army of about 9,000 men was trapped against the East River, facing annihilation by a larger British force. Strong winds and rain initially prevented British ships from blocking the escape route. Then, on the night of the evacuation, the wind calmed, allowing a silent boat retreat, and a thick fog rolled in, concealing the operation until morning. When the fog lifted, the British were stunned to find the Americans gone. This saved the Continental Army from destruction early in the war.
The Battle of Long Island, or what is also called the Battle of Brooklyn, or the Battle of Brooklyn Heights, is an example where the providential hand of God can be seen.
Although not well known, the Battle of Long Island is one of the first and is the largest battle of Revolutionary War. The future of America and world was forever changed by the amazing intervention that took place.
The British plan was to control New York City and the Hudson River, effectively cutting New England off from the rest of the colonies. Their only obstacle, the American-held town of Brooklyn at the western end of Long Island. 32,000 British soldiers opposed about 19,000 soldiers of the Continental Army. After the British force landed on Staten Island, General George Washington moved much of his forces across the East River from Lower Manhattan to defend Brooklyn.

A map of the battle
On August 27, 1776, the British attacked Brooklyn on three fronts. They attacked American forces directly on two fronts and sent a third force of about 10,000 men through a little-used pass to successfully outflank the Americans. With Washington’s army caught off guard and outnumbered, only a series of fortunate events saved the American Revolution.
First, a small group of 400 soldiers from Maryland were able to fight and save the army from a complete rout. This allowed a larger group of Americans to retreat to Brooklyn Heights and avoid capture. Rather than press their advantage, British General William Howe ordered his men to stop the attack and dig trenches around the Continental Army. He expected the Americans to surrender. He also expected British ships to sail around and cut off the Americans from their only line of retreat across the river to Manhattan. But the ships never came. Why? Because there was not enough wind to get them there.
This gave George Washington the night to secretly get 9,000 men to safety and keep his army intact. He ordered every available boat to be taken and used to get his army across the East River. Working through rain and darkness, the oarsmen in the boats crossed the river multiple times to deliver soldiers across to the other side. The only problem was that a large part of the Continental Army remained in Brooklyn as the sun rose. These men likely would have been killed or captured if they did not cross the river, losses the Americans could not afford.
However, a final fortune smiled down on the Americans from Above. A heavy fog settled over the area and the rest of the Continental Army was able to conceal their movements from the British. As the fog lifted, the British were left bewildered as they realized the Continental Army was gone.
The British captured New York on September 15, 1776, but they did so without destroying the Continental Army. The Revolutionary War continued, and with it came the ultimate American victory.
Without a few hundred tenacious soldiers, a lack of wind, and some heavy fog, there may have never been a United States of America!
Adapted from, "The Fog That Saved an Army"
https://1776history.com/2014/08/31/the-fog-that-saved-an-army/
Additional resource: The Battle of Long Island