It was the arrival of two ships from Bermuda that saved the colony. Those ships were had been wrecked in a storm and were initially stranded in Bermuda. There the would be colonists repaired them and with their holds full of sea turtles and birds, they were with difficult to proceed to Jamestown. There they found the starving and dehydrated colony that was trying to return to England. A prolonged drought had also fouled their water. The arrival of those two battered ships probably changed history.
One of my ancestors was aboard one of the ships that got shipwrecked on Bermuda, then repaired the boats and arrived at Jamestowne just in time to rescue the starving colonists. They had been trapped in the fort by the Powhatan Indians, so could not hunt or forage. On top of that the winter was so severe that the rivers froze solid. The world was undergoing a Little Ice Age.