Date: May 01, 2014
Magazine:
May 2014 Irrigation Advances

As March of 1991 opened, California had experienced five straight years of well-below average rainfall.  Water rationing and other conservation ideas were the rage and talks of draconian measures were commonplace.

Then March of that year delivered rain and snowfall levels 250 percent greater than normal throughout the state.  Reservoir storage, which was on average sitting at 17 percent of capacity at the beginning of the month, more than quadrupled by the end of the month.  Many of the news stories in April of 1991 reminded water users that one month of above-average rain — even well-above average rain — did not solve the problem and continued conservation was urged.  Whether the drought was over was the focal point of many arguments.

In fact, the persistent rain in March of 1991 did not signal the end of what would become a six year drought.  That year, rain totals were still only three-quarters of normal and the following year, precipitation levels reached only 85 percent of normal.  It wasn’t until 1993 when rainfall reached record levels throughout the state and total rain was at 155 percent of normal that the drought truly ended.

This year, unfortunately, there was no March Miracle leading to a debate about the end of the drought.  The April 1 snowpack and precipitation numbers were disappointingly low, despite a promising rainy start to March.  “This is dismal news for farms and cities that normally depend on the snowpack — often called California’s largest reservoir — for a third of their water,” said an April 1 press release from the California Department of Water Resources (DWR).

The April 1 snowpack survey showed that below average level of snow contained only 32 percent of average water content for the date.  Surveyors from the DWR skied high into the Sierra Nevada to measure the amount of snow there on that date.  The state measures the snowpack in the northern, central and southern Sierra each month during the wet season, typically from October through March. Those numbers are critical because they are a very accurate gauge of spring runoff, and determine just what percentage of their needs California farmers will receive this year.

“We’re already seeing farmland fallowed and cities scrambling for water supplies,” said DWR director Mark Cowin. “We can hope that conditions improve, but time is running out, and conservation is the only tool we have against nature’s whim.”

The April 1 survey is critical because it marks the peak of the snowpack.  In January, the water content was only 12 percent of normal, the lowest snowpack on record.

The March rain and snow offered some relief for ski resort operators, but it was too little and too late to have much impact on this year’s statewide drought.  Snowpack and rain measurements are so far below normal for this time of year that even sustained rainfall won’t end the drought.

California is in its third straight year of drought conditions, and according to the U.S. Drought Monitor, a federal website that tracks drought, 99.8 percent of the state is in a drought situation.  More than 23 percent of the state is in “exceptional” drought, the worst category.  Both percentages are at their highest level since the Drought Monitor was launched in 2000.

Those looking for a silver lining might want to read the Browning Newsletter, a subscription-based publication (browningnewsletter.com) that takes an analytical look at weather patterns and tries to forecast the future.

Author Evelyn Browning-Garriss, who calls herself a historical climatologist, believes that there is about an 80 percent chance that a sustained El Nino event will occur over the next several months and bring above-average rainfall and snow to the state this upcoming fall, winter and spring.

Browning-Garriss made her prediction in mid-April and was interviewed extensively by the media throughout the month.  She said she looks at thousands of years of data — including recorded information as well as that extracted from tree rings and other sources to forecast upcoming weather conditions.  In her newsletters over the past year, she claims to have predicted California’s continued drought as well as many other climatic conditions that have occurred.

She says that she looks at historical records, compares current conditions and gives a probability as to what will occur when similar conditions have persisted in the past.

With regard to an upcoming El Nino, she said that condition occurs when tropical Pacific Ocean waters, which make up about 10 percent of the earth’s surface, start to warm.  That changes weather patterns by putting more moisture in the clouds and creates stronger winds.  “When that happens, it usually blows lots of rain to California,” she said in one Central California radio interview in mid-April.

She added that the current tropical Pacific Ocean conditions forecast an 80-90 percent chance that El Nino conditions will exist in California for an extended period in the next 12 months.  She said these current conditions would typically result in “full-scale El Nino” for California about 60-70 percent of the time.

Browning-Garriss said that if the full-scale El Nino develops over the next several months the benefits to California will start to accrue in late summer.  “Instead of having a dry, dry summer, California will have a normal dry summer and the winter conditions will start to show up in late September.”

If the model plays out as she expects, this climatologist said above average rain will start to fall in October and persist through the spring of 2015.

Browing-Gariss did say that California is in the midst of what is typically about a 25-year cycle of dryer than normal weather.  She said the conditions began in 1998 and have persisted for the past 16 years.  She said the cycle typically last about 25-30 years before it goes in the other direction.  California, she said, is currently getting about the same rainfall that it received on an annual basis in the 1950s and 1960s.  She added that that does not mean that every year will be dryer than normal as there will be El Nino conditions on average above every four years spiking the precipitation totals.

To navigate its persistent water situation of many drought years surrounding only a few wet years, the longtime observer of the state’s water situation said California should build more reservoirs to capture those rains when they do come.  She said the state did a great job in the ‘50s and ‘60s of adding capacity, but has done little infrastructure work in the past four decades.

WG Staff Contact

Join Western Growers

Western Growers members care deeply for the food they grow, the land they sustain, the people they employ, and the community in which they live. 

You May Also Like…