Rainfall totals have always been a moving target

When Pat Craig was a reporter for the Press in the 1960s and 70s, he was asked by several readers if the winter of 1972-73 — a half century ago — set some kind of record for the amount of rain that had fallen on the Tracy area, beginning in September and continuing into the following summer.

Pat answered: “Sure, we’ve gotten more than enough rain this year — anywhere from 12.47 to 19.85 inches, depending whom you had listened to, but it isn’t a record.”

He said that’s what makes reporting which rain year has been the wettest a challenge, since a number of sources were reporting different totals for the annual rainfall.

For years, rainfall records were kept at the Southern Pacific office, and then it was the Tracy Fire Department, Banta-Carbona Irrigation District, several amateur meteorologists and the U.S. Weather Service at Stockton Metropolitan Airport. All provided slightly different rain totals for the season.

The Stockton total rainfall normally comes out at least a few inches more than the Tracy total, since our area sits in the middle of what meteorologists describe as a “rain shadow.” Rain clouds are diverted from this area while passing over the Altamont hills as they head this way in a northeasterly direction.

“According to the fire department, where records go back 10 years, this is the most rain we’ve had,” Pat reported. “but the Weather Bureau, which has figures going back to 1850, can name several years of more than 20 inches and a couple of years where the figures were above 30 inches.”

From my own experience in more recent years, the 20-inch figure for Tracy’s annual rainfall is close to the top. A lot depends how the totals during the winter months, usually adding up to around 11 or 12 inches, are augmented by heavy April showers. So far this year, the total through a week ago has been 12.91 inches, as measured by the Community Collaborative Rain, Hail and Snow Network. We’ll have to wait six weeks to find out if this year’s series of storms will continue into April, as I recall it did in 1983.

But at least we know that no year has climbed anywhere close to the 1850 record. I wonder what kind of rain gauge they used back in the mid-19th Century?

If only the late Paul Rinauro, known as the “Carbona Weather Oracle” for forecasting one-year weather patterns, were still with us. He might have known, citing Tracy “rain shadows” and all.

n Sam Matthews, Tracy Press publisher emeritus, can be reached at 830-4234 or by email at shm@tracypress.com.