If winter weather patterns persistently fizzle out, the Lake Tahoe region may experience more problems than just a dry season. It could mean consecutive years with below-normal precipitation.
This year's moderate El Ni-o, billed as strange and unpredictable, has failed to produce the amount of precipitation expected for the Pacific Coast from Southern California north to the lake.
December's strong start to the season subsided with a below-average January and disappointing February, with eight days left to go in the month.
For the Sierra, this El Ni-o is punctuated by a February with about 30 percent less rain and snow and a greater chance of being followed by a La Ni-a. The opposite of El Ni-o is characterized as a cold water mass that usually brings even less precipitation.
"If you're a betting person, you'd bet on a back-to-back El Ni-o and La Ni-a. And if that happens, that's when it starts to get serious," said John Kermond, chief climatologist with National Oceanic and Atmospheric Administration. "But Mother Nature still holds the aces."
Drought is the level of seriousness Kermond is worried about.
If La Ni-a follows the tropical weather phenomenon, sea-surface temperatures may decrease by as much as 10 degrees. Current water temperatures are reported as 1 degree above normal, which is still enough to cause global climate changes.
The National Oceanic and Atmospheric Administration points to the warm water mass that formed in late summer off the shores of South America -- a couple of months sooner than originally predicted -- as part of the reason for the dry spell. This may mean it ends as early as April, two months sooner than usual.
"It's still with us, but it's the most unusual event," Kermond said. "Southern California had six to eight weeks without a drop (before last week's storm). Usually by this time, houses are falling off the cliffs in Malibu."
He used the view outside his Washington, D.C., office as an example of the uncanny nature of this winter. A mild El Ni-o often brings an average amount of snowfall to the nation's capital, but recent storms gave the region its fifth-largest dump on record.
Tahoe's last snow and rainstorm, combined with snowmelt, raised the lake level by a few inches to 6,223.7 feet. The rim level is 6,223 feet.
"This has turned out to be a real bummer. (This El Ni-o) hasn't turned out to be a traditional one," said California Department of Water Resources Chief Hydrologist Morris Reuss, referring to the current dry spell. "February's not panning out so we may be heading for a below-average year," he said.
The weather forecast for the upcoming week shows sunny, clear skies with few chances of snow showers.
Reuss shared concern that the Sierra's prospects for precipitation are fast diminishing, with one more month of rain and snow left to push up the water level in the snowpack.
