Unrelenting dry conditions have placed most the state at the highest level of drought since monthly monitoring began in the late 1990s, according to the weekly U.S. Drought Monitor report released on Thursday.
The latest report shows that 58 percent of the state is at an exceptional level of drought — the highest level of intensity that the monitor uses. Portions of the state that aren’t at exceptional drought are at severe or extreme levels.
“It’s a testament to the fact that this drought has carried on for now more than three years, and it’s been accompanied by record-setting heat,” said Brad Rippey, a meteorologist for the U.S. Department of Agriculture and author of the report.
Strikingly, the report shows a nearly 22 percent jump from the previous week in the amount of the state that is under exceptional drought. Rippey said that the jump can be explained by the northern part of the state finally crossing over into the highest category of drought.
“With the recent heat and some of the wildfires and some of the reports coming out of the groundwater issues — as well as reservoir reports — they just kind of jumped that fence, getting on the other side of the 1 in 50 year drought,” Rippey said.
The monitor categorizes drought intensity according to how often an area has seen similar dry conditions in the 120-year historical record:
- The entire state has been categorized to be under a "D2" or severe drought level since early May.
- Nearly 82 percent of the state is currently under "D3" or extreme conditions, which is a type of drought typically seen once in every 20 to 50 years.
- The "D4" or exceptional drought is the highest category level and is a drought usually seen once in every 50 to 100 years.
The report also shows that the state’s reservoirs are short by more than a year’s worth of water. According to June data from the National Oceanic and Atmospheric Administration, 12 to 15 inches of rainfall would need to fall in a single month to bring the Los Angeles region out of the drought.
With months of summer conditions still to come, the likelihood of ending the drought soon is low. In fact, though Rippey said he doesn’t make predictions regarding the weather, he said that it’s likely exceptional drought conditions will spread.
“Common sense just tells you that the potential is there for further expansion, and that would be especially true as we get into the next wet season, like the fall and winter of 2014,” Rippey said. “If at that point we fail to see rains and mountain snows materialize, I think it would be a no brainer at that point to see further expansion of your D4.”
A map of California’s current drought conditions shows a maroon weal spreading out from the center of the state, indicating the majority of the state's land area is under exceptional drought.
Rippey said it wouldn’t be possible for the monitor to issue a higher category of drought, because the National Climatic Data Center has only recorded rainfall for the past 120 years. However, he said he and his peers have discussed what a higher category would look like.
“We would never use it, because we don’t have the database to support it, but something in the order of a 1 in 100 to 1 in 200 year drought would be the equivalent of what we would call this theoretical D5,” Rippey said.