How Hard Did it Rain

A Quick look at some local rain fall rates

In yesterdays Weather Blog, I reported that 8.73 inches of rain has fallen so far this month in Albany.  With today's break in the rain, the possibility of more heavy rain just days away, it was time to reflect on the past rainfall.  Just how hard did the rain fall?

December 7th the reported rainfall in South Albany* was 1.66 inches.

A majority of the rainfall was in a five hour period in the morning, with the heaviest rainfall over two one hour periods each separated by moderate rainfall over a three hour span. 

The first peak in the rainfall rate was from 6:44 to 7:44 am Monday, December 7th.  It was dark, winds with moderate gusts; a very gloomy way to start out a week. Almost one third of an inch of rain (0.29) fell in that sixty minute period.  This is raining Cats and Dogs (rate => 0.2 inches/hour).

The second peak, raining Elephants and Hippopotamuses was from 10:17 until 11:17 where another one third inch of rain (0.33) fell.  For one thirty minute period the rainfall total went from 1.26 to 1.44 inches, 0.18 inches in 30 minutes.   That is a rainfall rate of 8.64 inches in a twenty four period. That is raining Elephants and Hippopotamuses (rainfall rate >=0.3 inches per hour).

By the mid west gully washer standard our heavy rainfall may not stack up but our 1/3 inch of rain in an hour is the "Heavy" Rain Category according to the American Meteorological Association.

By the way, the next category according to the AMA is "Violent" Rain, that is massive drops falling at a rate of 2 inches an hour or more.

* - Albany Oregon Weather station 

Thirty Minute Rainfall Rates Albany (South), OR 12/7/2015


Note that three 1/2 hour periods where the rainfall rate was greater that 0.3 inches per hour. 



Amazing Facts on Subject

Highest rainfall recorded in one minute is 1.23 inches.  This event happened on July 4, 1956 at Unionville, Maryland. 

The one hour (60 minute) record is an amazing 12.0 inches of rain that fell on Holt, Missouri June 22, 1947.