Rainfall

Rainfall tally Precipitation amounts for the 24-hour period ending 5 p.m. Monday: Downtown L.A.... 0.94 inches Bel-Air ... 0.91 Long Beach ... 1.42 Claremont ... 1.06 Newport Beach ... 1.24 Corona ... 1.32 Source: National Weather Service

When it comes to Southern California's increasingly perilous fire season, you can blame both the lack of rain and the little rain we did have. Scientists at NASA's Jet Propulsion Laboratory and at Chapman University said satellite data show the effects of a steady and largely forgettable rainfall during a roughly four-day period at the end of January. JPL scientist Son Nghiem said the rain came just as much of the vegetation throughout the region was awakening from a dormant stage.

As a heat wave continued to sear much of the East with 100-plus temperatures Saturday, Chicago was pounded with record-breaking rainfall. At O'Hare International Airport, rainfall totals had reached 6.91 inches Saturday morning - the largest single-day rainfall since records began in 1871, according to ChicagoWeatherCenter.com. The highest previous daily total was 6.64 inches on Sept. 12, 2008. Commuters soldiered on their way, trying to deal with the effects of overnight storms.

A "May miracle" of almost perfectly timed, above-average rainfall helped firefighters battling the large Springs fire in Ventura County and guaranteed that Los Angeles would not break a dubious record. The city was on track to having its fourth-driest year since 1877. But with about 0.70 inches of rain falling in downtown L.A. just before noon, that is no longer the case. For firefighters trying to mop up the 28,000-acre wildfire that broke out last week under blistering temperatures, the rain couldn't have come at a better time - even if Southern California's fire season still looks to be an ominous one. PHOTOS: Springs fire Tom Piranio, a spokesman for the California Department of Forestry and Fire Protection, said it didn't rain enough in the actual perimeter of the blaze for people to need an umbrella, but it was more than enough to help firefighters slow the Springs fire's momentum.

A weekend storm dropped an additional half an inch of rain on Ventura County, bringing the season total to nearly 10 inches at the county Government Center, the flood control district reported Sunday. Heavy El Nino storms have already brought more than twice as much rain to the county as fell all last winter, and the rainfall total is two-thirds the normal amount for an entire rainy season, weather officials said. Last year, the county received 3.

Air pollution in China's industrial east appears to have significantly reduced light rainfall over the last 50 years, raising the possibility that cutting pollution could ease a severe drought in the region, according to a study released Saturday. Light rain -- anything from a drizzle to 0.4 of an inch in a day -- is also crucial for agriculture, as opposed to heavy rain, which triggers floods that can wash away crops. Researchers from the U.S. Department of Energy's Pacific Northwest National Laboratory found that the number of days of light rainfall in eastern China decreased by 23% from 1956 to 2005 because of air pollution.

The latest storm to hit the California coast brought only light rain and fog to Ventura County on Thursday, and some meteorologists are wondering whether this will indeed be the very wet winter that forecasters have been anticipating for months. Despite predictions of a rainier winter than in past years due to El Nino, the periodic warming of the eastern Pacific, Ventura County has actually had nearly 1 inch less rainfall this season than last year at this time. Although the rainfall is almost 2 inches above normal, with 7.95 inches recorded for the season at the Ventura County Government Center, it had rained 8.62 inches by this time last year at that location, according to the National Weather Service in Oxnard.

Two storm systems will begin moving into the region today and Friday, producing heavy rain and snow at times in Southern California, the National Weather Service said. The first storm system is expected to hit tonight, but it will be the weakest of the two, producing about half an inch of rainfall, said weather specialist Stuart Seto. Snow levels in the local mountains will be between 5,500 and 6,000 feet, with 2 to 4 inches of snowfall, he said. The storm is expected to taper off by Friday afternoon, Seto said.

Despite a gloomy June, Los Angeles is poised today to record its fourth year in a row with below-normal rainfall. From July 1 of last year to today, a period designated as a "rain year," only about 9 inches of rain fell compared to an average of slightly more than 15 inches, said Bill Patzert, a climatologist with the Jet Propulsion Laboratory in La Canada Flintridge. Southern California hasn't had an above-average rain year since 2004-05, when L.A.

The Times has just printed its semiannual rainfall chart for the years since 1877 (July 5). On my desk is a photocopy of a similar chart published in The Times on Aug. 15, 1886, that showed rainfall back to 1872-73. In those years, the Signal Corps kept the official records for local precipitation. Notice the heavy rainfall during that early period. The year 1875-76, however, would have been one of the driest years on record. 1872-73 ... 24.78 inches 1873-74 ... 21.67 inches 1874-75 ... 26.47 inches 1875-76 .....

WASHINGTON - Climate change may increase the risk of extreme rainfall in the tropics and drought in the world's temperate zones, according to a new study led by NASA. "These results in many ways are the worst of all possible worlds," said Peter Gleick, a climatologist and water expert who is president of the Pacific Institute, an Oakland research organization. "Wet areas will get wetter and dry areas will get drier. " The regions that could get the heaviest rainfall are along the equator, mainly over the Pacific Ocean and the Asian tropics.

Floodwaters that swept through the Midwest last week failed to recede Tuesday after another inch of rain fell in Illinois and surrounding states, and forecasters warned that more was on the way. Heavy rainfall and severe thunderstorms battered the region with half a foot of rain last week, inundating several small towns - including Marseilles, Ill., and Kokomo, Ind. - and causing damage from lower Michigan to Missouri. Water coursed through downtown Chicago, submerging cars, knocking out power to thousands of residents and forcing the cancellation of hundreds of flights from O'Hare International Airport.

Irrigation in California's Central Valley pours so much water vapor into the atmosphere that it significantly drives up summer rainfall and runoff in the Southwest, according to a new study. Using a global climate model and estimates of agricultural water use in the Central Valley, UC Irvine scientists concluded that increased evapotranspiration and water vapor export from the valley had a significant effect on the interior Southwest's weather patterns. Average rainfall during the region's summer monsoon season is 15% greater than it would be without the influence of Central Valley irrigation, and the extra precipitation boosts Colorado River flows by 28%, according to the researchers' computer modeling.

WASHINGTON - The impacts of climate change driven by human activity are spreading through the United States faster than had been predicted, increasingly threatening infrastructure, water supplies, crops and shorelines, according to a federal advisory committee. The draft Third National Climate Assessment, issued every four years, delivers a bracing picture of environmental changes and natural disasters that mounting scientific evidence indicates is fostered by climate change: heavier rains in the Northeast, Midwest and Plains that have overwhelmed storm drains and led to flooding and erosion; sea level rise that has battered coastal communities; drought that has turned much of the West into a tinderbox.

Argument has raged for decades over what doomed the ancient Maya civilization and spurred its people to abandon their awe-inspiring temples and pyramids in the rain forests of Mexico and Central America. Warfare, disease, social unrest and over-farming have all been cited as potential factors in the decline of a culture that was scientifically and culturally advanced for 750 years. A new study bolsters the theory that large-scale climate change was responsible for the society's demise - and argues that changes in global weather patterns were also responsible for its rapid rise.

WASHINGTON -- Federal officials warned Tuesday that slow-moving Hurricane Isaac could pummel southern Louisiana and neighboring states for more than two days, causing significant storm surge along parts of the Gulf Coast, dumping enough rain to cause widespread flooding, and spawning destructive tornadoes. "As the center of the storm comes ashore tonight, that will not be the end of the event, it will be just the beginning," Rick Knabb, director of the National Hurricane Center, told reporters on a conference call.

Israelis, facing the most serious drought in more than a decade, are being urged by the state water authority to shower with a friend. Authority spokesman Mordechai Yakobovitch said that shared showers and all other water saving measures should be adopted because of the third successive winter of low rainfall.

Is there any truth to the rumor that the water department is going to add "rain charges" to our bills? These would be predicated on pricing for each inch of rainfall, to make up for the water we didn't use. MORRIS KUSHNER Encino

With temperatures on the rise, Southern California was bracing for the arrival in earnest of fire season. On Monday, the Los Angeles County Sheriff's Department's Altadena station announced that the fire danger level in the Angeles National Forest had risen from "high" to "very high" — the fourth of five levels on the scale. Meanwhile, Supervisor Michael D. Antonovich announced the opening of 55 cooling centers across Los Angeles County to provide relief from the heat for the elderly.

Right about now, tiny goldfields and purple mat should be erupting in carpets of color on the desert floor at Joshua Tree and Death Valley national parks. The gentle hills of the Antelope Valley poppy reserve should be turning bright orange with thousands of California poppy blossoms. But so far this spring, wildflowers in local deserts and mountains are in short supply. Even the rainstorm that swept through Southern California last weekend won't be able to rescue what flower watchers say is turning out to be a disappointing year.