When the rotten egg smell wafted into the Santa Clarita United Methodist Church in Saugus on Monday morning, Kathy Gray thought the church's sewer pipe had burst.
More than 70 miles to the east, steelworker Chris Tatum's nostrils got the punch in Riverside. He assumed a brush fire had just broken out.
"It reeks," he said. "It smells like rotten mush."
Southern California awoke Monday morning to a foul odor that wouldn't go away.
Residents clogged 911 lines with calls, prompting health officials from Ventura County to Palm Springs to send investigators looking for everything from a toxic spill to a sewer plant leak.
The prime suspect, however, lay more than 100 miles away from Los Angeles. The leading theory is that the stink was caused by the annual die-off of fish in the Salton Sea. Officials believe Sunday evening's thunderstorms and strong winds churned up the water and pushed that dead-fish smell to points west overnight.
Officials from the Air Quality Management District and other agencies said they have never dealt with a stench quite like this. Although the fish die-off usually causes foul odors in parts of the Inland Empire, officials cannot recall it traveling this far.
"It's very unusual that any odor would be this widespread, from the Coachella to Los Angeles County," said Sam Atwood, spokesman for the South Coast Air Quality Management District. "We're talking well over 100 miles. I can't recall ever confirming an odor traveling that distance."
The Salton Sea did track 40-mph winds Sunday night, and officials said that probably served as a trigger.
"The winds could have stirred up the water," said Bill Meister, president of the Sea and Desert Interpretive Assn. "Because the lake is so shallow, and there is 100 years worth of decayed material at the bottom, you'd get that rotten egg smell."
At its deepest points, the Salton Sea is only about 50 feet, said Andrew Schlange, general manager of the Salton Sea Authority. The 360-square-mile body of murky, highly saline water is also receding into the desert. More water is evaporating from the sea than is flowing in from agricultural runoff. In some places the falling waterline has uncovered thermal fields studded with features like geysers and boiling mud pots spewing clouds of steam and sulfur dioxide gas that smells like rotten eggs.
The "accidental sea" was created in 1905 when the Colorado River jumped its banks during a rainy season and gushed north for months, filling an ancient salt sink. It's 35 miles long, 15 miles wide and 227 feet below sea level.
Schlange said it's a common occurrence for fish populations to explode and then suffer die-offs when oxygen is depleted from the sea.
"The problem is [the odor] would have to have migrated 50 to 100 miles, without it being dissipated by mixing with other air. It doesn't seem possible," he said. "I've been in Southern California my whole life, and I'm not aware of any time in the past where the odor from the Salton Sea has migrated as far as people are telling us."
Schlange said several factors could explain the far-traveling smell. In the last week, the blistering heat reduced oxygen levels in parts of the Salton Sea, causing fish to die and settle to the bottom, where they decomposed with other organic material.
Then a thunderstorm barreled through the area Sunday night, churning moisture-laden air counterclockwise and pushing it from the southeast.
"That atmospheric flow would bring the smell up from the Salton Sea into the L.A. Basin here," said Bill Patzert, a climatologist for the Jet Propulsion Laboratory in La Ca?ada Flintridge. "This was an ill wind that dropped from the Coachella Valley into the Inland Empire cul-de-sac and boogied west ? into the San Gabriel Valley and L.A. County. The stink is normal around the Salton Sea. The strong winds are the unique occurrence that moved it into our 'hood.' "
Whatever its provenance, the stench made the rounds.
Pacoima comedian Jose Chavez said at first he thought some eggs he bought had gone bad.
"When I realized it wasn't the eggs, I thought it must be me, so I changed my clothes," Chavez said. "Finally I saw the reports.... With the weather the way it is, the smell was awful."