About these ads

Global warming could reduce Sierra Nevada runoff by 25 percent

Increased plant growth projected to use more water

In the lengthening nights of October, the Snake River starts to freeze.

Global warming is likely to have a big impact on mountain runoff. bberwyn photo.

Staff Report

FRISCO — Forests and brush moving up mountainsides as the climate warms could take a big gulp from streams and rivers, potentially cutting runoff by as much as 25 percent by the end of the century. Warmer temperatures will accelerate plant growth, triggering more water absorption and evaporation, according to researchers with  UC Irvine and UC Merced.

“Scientists have recognized for a while that something like this was possible, but no one had been able to quantify whether it could be a big effect,” said UCI professor of Earth system science Michael L. Goulden. “It’s clear that this could be a big effect of climate warming and that water managers need to recognize and plan for the possibility of increased water losses from forest evaporation.”

According to the researchers, runoff from mountain ranges is vulnerable to temperature hikes that lengthen growing seasons and result in more vegetation growth at high elevations, according to the study, to be published this week in the Proceedings of the National Academy of Sciences. Continue reading

Climate: How hot will it get in Colorado?

State releases draft climate change report, comments wanted

dg

How warm will it get in Colorado?

By Summit Voice

FRISCO — Climate experts say it’s about to get warmer —probably much warmer — in Colorado. A draft state climate report released this week for public comment shows that Colorado has warmed by 2.5 degrees Fahrenheit in the past 50 years. By the middle of this century, summer temperatures will be higher than in all but the hottest years, with another 2.5 to 5.5 degrees of warming expected. Continue reading

About these ads

Climate: Storms bolster Colorado snowpack

ij

Colorado’s snowpack is above average as of Feb. 1.

Feb. 1 snow survey results suggest decent spring runoff for most of the state

By Summit  Voice

FRISCO — Colorado’s snowpack surged to above average in late January thanks to a strong storm that brought snow statewide, federal water experts said last week. The Feb. 1 snow survey showed the average snowpack across the Colorado mountains at 107 percent of average, and 152 percent above last year’s Feb. 1 reading.

As of Feb. 1, only the Upper Rio Grande (82 percent) and San Juan (79 percent) basins in the southern part of the state were below average, according to the USDA’s Natural Resources Conservation Service. Continue reading

Colorado snowpack lingering in the northern mountains

Southern part of state still gripped by drought

sdf

Colorado’s June 5 snowpack map is a patchwork quilt of contrasts.

By Summit Voice

FRISCO — Springtime in the Rockies was a tale of two states in Colorado. The snowpack rebounded in the northern mountains, which benefited from a series of wet spring storms, but the southern half of the state was dry and warm, with serious drought conditions persisting in the Rio Grande, as as the San Miguel, Dolores, Animas and San Juan basins.

This year’s statewide snowpack peaked April 21, several weeks later than the average date, and cool weather helped further delay snowmelt across the higher elevations, resulting in a statewide June 1 snowpack  at 92 percent of median, according to Randy Randall, acting State Conservationist with the NRCS.

“This respectable percentage is due mainly to the generous amount of snow that remains across northern Colorado. In contrast, the snowpack in the southern portion of the state is nearly depleted even at the higher elevations,” Randall said. Continue reading

Colorado: Dust layers a factor in record-early snow melt

Report links wind-blown dust with early runoff

Dust from the desert Southwest is visible on the snow at Loveland Pass, Colorado in this file image from 2010.

NASA Satellite images can trace the dust plumes back to their source.

By Summit Voice

SUMMIT COUNTY — Along with above-average temperatures and dry and sunny weather, spring dust storms in March and April likely were a significant factor in this year’s record early snow-melt season, according to the Silverton-based Colorado Center for Snow and Avalanche Studies.

Snow that’s darkened by wind-deposited dust absorbs much more heat and hastens the warming of the snowpack to an isothermal state (32 degrees from top to bottom).

In its year-end report, the center explains that the dust layers continue to absorb and add solar energy to the snowpack long after the original dust layer is deposited.  Continue reading

Colorado: Snowpack and runoff near record lows

Statewide snowpack now just 19 percent of average; summer streamflows expected to be less than 50 percent of average

Straight Creek, Dillon’s primary water source, could see record low stream flows this year. PHOTO BY BOB BERWYN.

By Bob Berwyn

SUMMIT COUNTY — The snowpack and runoff news keeps getting worse and worse in Colorado, as April brought another big drop in the numbers. The downward trend doesn’t bode well for the summer, and while reservoir storage is currently just above average statewide, those levels will quickly drop when irrigation season begins.

In Summit County measurements at Hoosier Pass by the Center for Snow and Avalanche Studies show that, at times, the snowpack was melting at a rate of an inch per day, accelerated by a layer of dark-colored dust that reduced the snow’s albedo.

“Statewide snowpack looks to have peaked around March 12, a month ahead of the average peak date, and began melting in late March at rates typically not observed until May,” said Phyllis Ann Philipps, State Conservationist with the Natural Resources Conservation Service. Continue reading

Drought conditions expand in north-central Colorado

March precipitation across the intermountain West shown as a percentage of normal.

Spring and summer runoff may reach record-low levels 

By Summit Voice

SUMMIT COUNTY — The mid-April snowfall helped reduce the immediate fire danger, but didn’t do much to alleviate the season-long moisture deficit. In fact, the region as a whole is drier now than it was at the beginning of March, according to the Western Water Assessment’s April report.

To-date, April precipitation at the Dillon weather observation site is 88 percent of average, at .65 inches. For January through March, the Dillon site has measured 1.94 inches of water compared to the average 2.74 inches, which is 71 percent of the historic average.

On April 1st, 17 Colorado SNOTEL sites set new record lows, while 16 others were near-record lows. By April 9th, several sites had either melted out with record early melt-out dates or were on a likely trajectory to do so.Spring and summer runoff in some areas may approach record-low volumes. Only 5.2 percent of the country still is covered by snow, the lowest level since 2004. Last year at this time, it was 22 percent. Continue reading

Follow

Get every new post delivered to your Inbox.

Join 7,857 other followers