The Lyell Glacier, one of the largest in the Sierra Nevada, has stagnated and is no longer moving downhill, according to a recent study conducted by National Park Service scientists and the University of Colorado.

Scientists have been monitoring the movement of Yosemite's largest glaciers by placing stakes in the ice and tracking their positions over a four-year period.

Data collected from stakes placed on the Lyell Glacier showed that no movement has occurred within the last several years. Since 1900, the glacier has decreased in size by 60% and has thinned by about 120 vertical feet.

"The Lyell Glacier has historically been recognized as the largest glacier in Yosemite and the second largest in the Sierra Nevada," Yosemite geologist Greg Stock said. "However, the lack of movement suggests that the term 'glacier' no longer accurately describes this feature."

Downhill movement is a defining feature of a glacier. The adjacent Maclure Glacier is still moving at its historical rate, about one inch per day.

Events

The Red Balloon Race

When: Saturday

Where: Fig Garden Shopping Center, Fresno

Fresno's newest footrace benefits Children's Hospital Central California and is sponsored by Soul 2 Sole Sports.

Runners will begin at Fig Garden and make a 5-kilometer clockwise loop around Palm, Bullard, Maroa and Shaw. Lanes on each street will be closed during the run.

Advance registration is $25 ($10 for kids 12 and under). Prices go up $5 on Saturday. Details: theredballoonrace.com.

Hensley Lake Offroad Races

When: Sunday

Where: Hensley Lake

Run trails in the Madera County foothills, ride your mountain bike or do both.

It kicks off at 8 a.m. with a 10-kilometer trail run, followed by a duathlon (2-mile run, 10-mile bike, 2-mile run.) at 10 a.m. and mountain bike racing at noon. Kids' events also offered.

Fees are $35 for the run, $40 for the duathlon and $20 for the mountain bike races. Details: trithis.org.

News & notes

-- Saturday is the second open house at the McKenzie Preserve, 2,960 acres of protected foothills on the north side of Auberry Road between Friant and Prather. Hours are 9 a.m. to 4 p.m. and there will be a $1 parking fee. Details and directions: sierrafoothill.org.

-- Tour the San Luis National Wildlife Refuge -- home to tule elk, snow geese and sandhill cranes -- on Saturday with the San Joaquin River Parkway. Fees are $15, which does not include transportation to Los Banos. Sign up at riverparkway.org.

-- The 2013 Valley Runner of the Year Series gets under way Feb. 13 with the Race Judicata Fun Run in Old Town Clovis. Details: runsierra.org.