He said he had checked the MetService weather report the night before but said the deluge was unexpected.
As day broke the damage became clear.
"There was the usual debris, slash and logs. There were whole trees and they go through the wires and snap posts," he said.
"Whole trees with root balls get washed down and act like battering rams."
While there was a substantial amount of damage to clean up there was some relief it was not as bad as the July floods two years ago when there were four downpours that continually washed through forest debris.
Alexander, who has been farming the block of land for more than 40 years, said in the early years he did not have such a problem as there were no pine plantations being harvested in the area.
"Once they started harvesting all the cuttings seemed to get in the waterways."
Police had reports of Mangakahia Rd being closed because of floodwaters at about 9.30am yesterday. Vehicles, including a milk tanker, were unable to pass through.