Nature up close: Sierra Nevada, Death Valley and the rain shadow effect

By “Sunday Morning” contributing videographer Judy Lehmberg. The beautiful Sierra Nevada’s name translates very literally from Spanish as “mountain snowfall,” meaning snow-covered mountains.  The reason why the peaks are snow-covered and why hot, dry Death Valley is east of the Sierra Nevada range is the same: They are both the result of the rain shadow effect.  To understand how this terrain-induced meteorological effect causes precipitation to occur in one place and dry, hot deserts in another, a little knowledge of relative humidity is needed. The Earth’s atmosphere contains water molecules in the gaseous state, and these create pressure; the more water molecules, the greater the pressure. The higher the temperature, the greater maximum amount of water the air can hold, and therefore higher vapor pressure. The relative humidity is defined as the ratio of vapor pressure present divided by the maximum vapor pressure at that temperature. When the weather reporter says the relative humidity is a muggy 75%, this means the water vapor pressure in the air is 3/4 of the maximum possible at that temperature. Dew, rain and snow often are stripped from moist air when the dew point is reached. For example, suppose the air temperature is T1, and the vapor pressure is about 2/3 of the maximum vapor pressure at that temperature; if the air is cooled, then at some lower temperature (T2), the vapor pressure of water in that air would be maximum, and dew, rain or snow may form. As warm moist air is deflected upwards by mountain ranges, the air cools, its capacity to hold water decreases, the saturation point is reached, and water begins to be stripped from the air as dew, rain or snow on the windward side of the mountain. After passing the top of the mountain, this cold, dry air begins to descend. As it descends, it warms. The relative humidity drops to a low number and the air acts like a giant hair dryer on the leeward side of the Continue Reading

Wet week ahead as rain returns to Bay Area, snow to Sierra Nevada

By Mark Gomez | [email protected] | Bay Area News Group PUBLISHED: March 12, 2018 at 5:58 am | UPDATED: March 12, 2018 at 6:52 am Northern California’s rainy season is not quite over. A series of storms are expected to deliver rain to the Bay Area this week and snow to the Sierra Nevada, with another system slated to possibly bring more precipitation next week, according to the National Weather Service. The first storm is forecast to impact the North Bay on Monday night, then move south through the entire Bay Area, according to the weather service. Rainfall totals through Wednesday range from 1 to 2 inches in the North Bay to one-quarter of an inch to 1 inch for locations south of the Golden Gate, according to the weather service. Here are the forecast rainfall amounts through Wednesday. Additional rain is expected Thursday through Saturday. — NWS Bay Area (@NWSBayArea) March 12, 2018 Along with the rain, breezy conditions are expected, with wind gusts up to 40 mph. A second system is expected to impact the Bay Area from Thursday to Saturday, with similar rainfall totals, according to the weather service. In the Sierra Nevada, the two storms could deliver several feet of new snow, according to the weather service. Major snowstorms in late February boosted the overall snowpack in the Sierra Nevada Range from 22 to 38 percent percent of the historic average. Stormy weather returns to interior #NorCal tonight into Tuesday and continues through the week. Snowfall will once again be measured in feet over the mountains while 1-3 inches of rain will be possible in the valley. Plan travel accordingly! #CAwx — NWS Sacramento (@NWSSacramento) March 12, 2018 The late-season storms not expected to pull Northern California out of its seasonal rainfall deficit. Rainfall totals across Northern California generally range from 50 to 60 percent of normal, including Oakland (58 Continue Reading

Blizzard warnings in effect for Sierra Nevada as major storm slams Northern California

A frigid storm moving in from the Gulf of Alaska will dump several feet of snow on Northern California mountains over the next few days, bringing whiteout conditions and dangerous wind chills.The storm will span most of the Golden State and has triggered blizzard and avalanche warnings in the Sierra Nevada and flash flood watches and the threat of floods and mudslides across the burn areas of Southern California.“It’s the biggest storm of the season,” said Jim Mathews, a meteorologist with the National Weather Service in Sacramento. “Of course, February was a dud of a month, so March is coming in like a roaring lion.”Forecasters are predicting up to 7 feet of snow in the Sierra Nevada, with up to 10 feet possible in the highest elevations in the mountain range “where no man lives,” Mathews said.“We’re measuring snow by the yardstick instead of by the foot rulers this time,” he said.It’s too early to say whether the storm portends a March miracle capable of pulling California’s snowpack out of the doldrums, said Michael Anderson, the state climatologist with the Department of Water Resources.The snowpack in the Sierra Nevada had a snow-water equivalent of 24% of average on Thursday, state officials said. Sierra snowpack traditionally makes up one third of the state’s water supply.But thanks to the historically wet winter of 2016, the picture isn’t as dire as it could be after the last several months of dry conditions, Anderson said.“In terms of having a base flow coming out of the Sierra into the larger reservoirs, it still seems to be holding up despite the dry winter,” he said.When the current storm passes, the snowpack could see an increase of 25%, he said.By mid-morning Thursday, the Boreal Mountain Ski Resort near Donner Lake had received a foot of snow. The Squaw Valley Alpine Meadows Resort near Lake Tahoe had received 7 inches, and Bear Valley between Lake Tahoe Continue Reading

Cold air, light snow to make it ‘feel like winter’ in Sierra Nevada

By Mark Gomez | [email protected] | Bay Area News Group PUBLISHED: February 16, 2018 at 8:15 am | UPDATED: February 16, 2018 at 11:22 am Bay Area residents planning a getaway in the Sierra Nevada for the upcoming three-day weekend can look forward to conditions that will feel like winter: daytime high temperatures near or below freezing with light snow showers. However, the amount of snowfall Sunday and Monday is expected to be minimal – just a few inches of new powder – and will do little to boost the Sierra Nevada’s depleted snowpack, according to the National Weather Service. “We need to be measuring in feet to be helping out in that issue,” said Zach Tolby, a meteorologist with the weather service in Reno. “We’ll get a little bit of fresh snow. It could freshen up the slopes. “It will definitely feel a lot like winter, some of the coldest air we’ve had in the region for the whole season.” Saturday is expected to be pleasant across the Sierra Nevada, with sunny skies and temperatures ranging from 45 to 55 degrees, according to the weather service. Temperatures will drop Sunday, with daytime highs ranging from 35 to 45 degrees. Monday will be even colder, with expected highs ranging from 24 to 29 degrees. The drop in temperatures is the result of a cold front dropping down from Canada, straight over the Sierra Nevada, according to the weather service. Along with frigid temperatures, 1 to 3 inches of new snow is expected Sunday, with the possibility of lingering snow showers Monday. Meteorologists with the weather service in Reno call this type of storm system a “slider” because it moves north to south directly over the Sierra Nevada, instead of east to west over the Pacific Ocean. Because slider storms “don’t come over the ocean, they don’t have much moisture with them,” Tolby said. “Our big storms come off the ocean and bring in moisture,” Continue Reading

Storm delivers rain to Bay Area, snow to Sierra Nevada

By Mark Gomez | [email protected] | Bay Area News Group January 25, 2018 at 6:56 am A storm system continues to move through the Bay Area and Northern California on Thursday morning, likely bringing the last round of January rain to the region. Much of the Bay Area received a decent soaking overnight, with rainfall totals generally ranging between one-quarter to one-half inch. As of 5 a.m. Thursday, rainfall totals around the Bay Area include Santa Rosa .69 inches, San Francisco .43 inches, San Rafael .39, Redwood City .39, San Jose .36 inches, Oakland .24, Concord .20. Scattered showers are expected Thursday morning and will become more numerous by the afternoon with a slight chance of thunderstorms for the North Bay, according to the National Weather Service. Colder temperatures are also expected, with daytime highs remaining in the 50s, according to the weather service. “We’re looking at pretty much a dreary, wet” Thursday, said Drew Peterson, a meteorologist with the weather service. “It’s not going to be heavy rain we got yesterday, but off and on showers.” Peterson added rainfall totals Thursday could range from two-tenths to four-tenths of an inch. Beginning Friday, the Bay Area is expected to begin a stretch of dry weather lasting through next week, according to the weather service. Peterson said the stretch of dry weather could last into the first week of February. “It looks like we’re dry through the next 10 days,” Peterson said. In the Sierra Nevada, up to 2 feet of snow was expected, and there were reports of heavy snowfall overnight, according to the National Weather Service in Sacramento, which issued a winter weather warning through 10 a.m. Friday. Thursday night, chain controls were in effect for stretches of Interstate 80, Highway 50 and other roadways, according to the California Highway Patrol. January has been a wet month for much of the Bay Area. As of midnight Continue Reading

In the Sierra Nevada, they’re putting the trees to work

By CALmatters | January 24, 2018 at 5:24 pm By Julie Cart, CALmatters This is going to be a big year for one of the state’s smallest agencies. As California redoubles its efforts to reduce greenhouse gases, officials are rooting around for new ways to meet the state’s goals. Included in their plan: recruiting billions of redwood, oak and pine trees to help diminish planet-warming gases by pulling carbon dioxide from the atmosphere. It’s a major pivot, from regulating harmful emissions solely from factories and cars to calling on nature to pitch in. Officials say 2018 is the moment for the state to harness, and fully measure, the role forests can play in addressing the pressing problems of wildfires and the dangerous releases of carbon that occur when millions of forested acres burn. Both issues are accelerating in alarming, parallel lines. A good bit of the work will fall to the Sierra Nevada Conservancy, one of 10 conservancies within the state’s Natural Resources Agency. The group—two dozen multitasking scientists, biologists and planners in a nondescript office park in Auburn, an old gold-rush town in the Sierra foothills—was born in 2004 with a mandate nearly as vast as the region. Like the state’s iconic coastline, the Sierra Nevada mountains are a defining feature of California, rising sharply to dizzying elevations, topping out at Mount Whitney’s 14,500 feet, the highest peak in the lower 48 states. The range, tracing the spine of the state across 22 counties from the Oregon border to deep inside the Mojave Desert south of Bakersfield, holds most of California’s forested land and is the source of 60 percent of the state’s drinking water. The conservancy is charged with restoring the Sierra’s environmental and economic health, on a modest $4.5 million annual operating budget derived entirely from the environmental license-plate fund. The bulk of its work, such as facilitating research and Continue Reading

Study: Loss of water in drought caused California’s Sierra Nevada to rise almost an inch

By The Associated Press | PUBLISHED: December 13, 2017 at 12:04 pm | UPDATED: December 13, 2017 at 12:17 pm LOS ANGELES — A new NASA study says loss of water from rocks during drought caused California’s Sierra Nevada to rise nearly an inch (24 millimeters) in height from October 2011 to October 2015. The study also found that in the following two years of increased snow and rain, the rocks in the range regained about half as much water as was lost during the drought and the height of the mountains has fallen about half an inch (12 millimeters). Research leader Donald Argus of NASA’s Jet Propulsion Laboratory is discussing the study Wednesday at an American Geophysical Union conference in New Orleans. The study suggests significantly more water was lost from cracks and soil within fractured mountain rock during drought and gained during heavy precipitation than hydrology models show. Continue Reading

Sierra Nevada is taking its Beer Camp global, casting a wide net for craft brew lovers

Sierra Nevada's Beer Camp series is going global. The third edition of the brewery's 12-pack of collaboration beers searched far and wide for inspiration. The result is a variety assortment of brews from six international and six stateside brewers. The range of beer styles is as diverse as the geography of the participants, reflecting a booming worldwide market for craft beer. Sierra Nevada's collaborations include Copenhagen-based Mikkeller's Thai-Style Iced Tea Ale, to an East Meets West IPA from Tree House Brewing in Massachusetts, and Raspberry Sundae Ale with California's The Bruery. "The craft beer revolution has spread from the U.S. to pretty much every country in the world, and we thought 'let's invite brewers we know and respect around the globe as a celebration of craft brewing and the spirit of collaboration,'" Ken Grossman, Sierra Nevada Brewing's founder and CEO, told CNBC recently. The task is not always easy, he told CNBC. "There a lot of very small brewers that maybe produce a few hundred kegs a year [and] are popping up around the country," said Grossman. "They're finding a few bars and restaurants who will support their branding, making it a little more challenging for more established brands to get on the shelf or get into the bar for a tap handle." Continue Reading

Backpacking the John Muir Trail in the Sierra Nevada range is tough but rewarding

The most arduous endeavors often have the biggest payoffs. That’s how it is with backpacking the John Muir Trail. The 210-mile wilderness trek in the Sierra Nevada range of California, named for Scottish naturalist John Muir, takes a toll. One climb after another — up and down mountains with altitudes ranging from 4,000 to 14,000 feet — taxes your leg muscles and breathing. Shoulders strain from shlepping 25- to 35-pound packs. Weather issues range from snow to rain to hail to heat and cold. But the rewards are legion — pristine alpine lakes, gorgeous meandering rivers and streams, coyote and marmot sightings, lots of wildflowers, and the feeling of traveling in the untamed natural world — surviving and actually thriving without a cell phone. A complete hike of the popular trail, from Happy Isles in Yosemite Valley to Mount Whitney, can take three weeks or more, so many opt to do sections at a time. That’s what I did late this summer — accompanied by my wife and 19-year-old son. I did about 80 miles over eight days, starting at Tuolumne Meadows. (I’d been inspired by the Cheryl Strayed memoir “Wild.”) Stopping at Yosemite and staying a day or two is a good way to acclimate yourself to the altitude. The Park is a national treasure, with a zillion backcountry things to do (climbing, hiking, riding, fishing, rafting, etc.) and mind-blowing scenery. We stayed a day at Yosemite Lodge and a day at Tuolumne Lodge. The tent cabins at Tuolumne featured wood burning stoves and wool blankets on the beds. (It gets chilly at night, even in late July.) Starting out, we had it “easy” — seven or eight miles along the Lyell Fork of the Tuolumne River, the only lengthy level area on the trail. Then, the climbing began as we went over Donohue Pass, and began the up and down that marks most of the time on the JMT. The first few days were, in truth, tough: Continue Reading

Nearly $2 billion worth of marijuana seized in California’s Sierra Nevada range

Sorry, stoners.California cops said they seized and destroyed $1.7 billion worth of marijuana during a three-week sweep in the Sierra Nevada range, according to the BBC.In addition, 97 people – mostly Mexican nationals who authorities believe are involved in a drug ring – were arrested.President Obama's drug czar, Gil Kerlikowske, said industrial-sized plantations of marijuana that was being illegally grown were discovered in the mountains. Dubbed "Operation Trident," about 450 agents destroyed more than 432,000 marijuana plants and confiscated nearly 500 pounds of processed cannabis.Margaret Mims, Fresno County sheriff, said the fields jeopardized the safety of local residents."They continue their criminal conduct during their off-season with other illegal drug and violent activities in our local communities," Mims said, referring to organized crime gangs. Join the Conversation: Continue Reading