For those stranded by a flood, disaster experts say survival depends on access to oxygen, food and water. Catastrophic flooding along the Nepal-China border has killed hundreds and left thousands more missing. On Monday, rescuers in Nepal raced to free hundreds of workers thought to be trapped in hydropower site tunnels buried in mud. Experts say the first 72 hours are critical as the chances of survival drop without access to clean water. Access to breathable air is another key to survival. Suffocation worries grow the longer people are trapped.

Federal officials have announced sharp water cuts for the next two years for three Western states that rely on the imperiled Colorado River. Under the Bureau of Reclamation’s plan, California, Nevada and Arizona will reduce water use collectively by 1.25 million acre-feet annually during that period with the possibility of larger cuts depending on conditions. Arizona will see the biggest cuts. Upstream states Colorado, Utah, Wyoming and New Mexico do not face any for now. Last winter saw the worst snowpack on record for the Colorado River Basin. That depleted critical reservoirs to record lows. The states have been unable to agree on how to share the water long term.

Survival after an earthquake depends on factors like weather and access to water and air. Experts say victims can survive for a week or more if their injuries aren't severe and the weather is mild. Two days after a deadly earthquake in western Colombia, rescue teams are racing to find survivors. Most rescues happen within 24 hours, but chances drop each day. A survivable void space, like under a sturdy desk, can increase survival odds. Air and water are crucial as time passes. Temperatures can affect survival and rescue missions.