Over the weekend, a potent winter storm forced rangers to shut down access to Yosemite National Park. Heavy rains drove the Merced River over its banks and flooding procedures were put into effect.
As a precaution, park employees were evacuated to a Red Cross Shelter and access to the park was closed on Friday after officials became concerned that the torrential downpours predicted with the incoming weather front would trigger flooding similar to 1997.
By the middle of the afternoon, the Merced was already dropping back to flood stage. Officials said the park will be open only to day visitors on Tuesday. Full services will be back underway on Wednesday. Travel within the park will be impacted by high water and also rock slides that have closed El Portal and Hetch Hetchy roads.
Officials said the Merced River reached flood stage at the Pohono Bridge on Sunday night and peaked at 12.7 feet at 4 a.m. Monday.
“So we ended up cresting at 10,500 cubic feet per second,” said hydrologist Katherine Fong. “So that puts us just above a 10-year flood.”
Fong is one of several hydrologists faced with the wildly complex task of predicting the behavior of a river being fed from every direction. She said the lack of real damage following this 10-year flood is no accident.
“The 1997 flood — which is kind of our flood of record — re-wrote the map in Yosemite Valley in terms of where infrastructure is,” explained Fong. “All the waterfalls — Yosemite and Bridal Veil — they were the biggest I’ve ever seen them, said Fong. The biggest that some people who have been here 20 years have ever seen.”
NOAA calls for more precipitation throughout the week but with lower snow levels.
“The big weather story for today (and the next several days) is the ongoing heavy rain and mountain snow event across California and the rest of the Northwest states. Very heavy rainfall is falling across much of northern California today with a significant ice event unfolding farther north across northwest Oregon and into southwest Washington (including the Portland region) and the Great Basin.”- NOAA
From Monday’s NOAA forecast, 24 Hour Precipitation Total – Day 1: