A new study from the National Center for Atmospheric Research says droughts in California and the Southwestern states are becoming more frequent, and days of steady rainfall may be also increasingly rare, according to a story on csmonitor.com.

The new study is based on broad storm patterns as opposed to day-to-day rainfall data, and the findings suggest the primary source of rain and snow in the Southwest originates from low-pressures storms coming in from the North Pacific Ocean and along the coast of Washington.  For the last 35 years, those types of storms have been forming less and less frequently.

Previous studies of tree ring data suggest that there have been a number of “megadroughts” in the region, some lasting for 20 years or more , but the model for life in California now is based on many years of unusually high amounts of rainfall in the area.

Professor Scott Stine of California State University, East Bay, who has conducted some tree studies himself, says it was easy to forget we consider the last 150 years to be normal, but past history shows many periods of drier decades and much drier centuries.  Some researchers say the area is currently undergoing a drier-than-normal period that began some 17 years ago, after an El Nino event.

The study’s researchers are basing their predictions of drier weather on data collected between 1979 through 2014, a period that included two major droughts that peaked in 1998 and 2000.  Figures from the National Oceanic and Atmosphere Administration suggest those droughts were similar to one’s the region faced in the 1930’s and 1950’s as well.

They say the findings point to the need to conserve more water in the area than the region has in recent decades, and may lead to adopting a more water-conscious life style, similar to the early settlers of the west.  This paints a grim picture for residents of the area where some of the toughest battles faced are over water rights, and will likely increase along with the growing populations competing for the precious resource.

Findings from the study were published in the journal Geophysical Research Letters.