On Sunday morning, May 18, 1980, an earthquake that measured magnitude 5.1 triggered an eruption of Mount Saint Helens in Washington state that did not fully cease until 1986.
The force of the eruption destroyed more than 200 homes and more than 185 miles of roads, according to the United States Geological Survey (USGS). The lava flow from the volcano scorched 230 square miles of forest. By the time the eruption ended, 57 people had been killed.
"A volcano can go from nothing to a very large eruption in a very short time," said USGS Hydrologist and Outreach Coordinator Carolyn Driedger. "Mount Saint Helens only took one week to go from nothing to a full eruption."
Since that day in May 1980, scientists at the USGS have been monitoring conditions at Mount Saint Helens for signs of a future eruption.
"We learned in 1980 with Mount Saint Helens and we changed how we do business and how we monitor these explosive volcanoes," Driedger said.
This May 18, 1980 eruption photo was taken from the southwest of the Plinian eruption column by Robert Krimmel.
Teams of scientists use seismographs to monitor the movement of magma below the surface of the volcano. They use GPS units to measure the movement of rocks and changes in the volcano at ground level and they measure the gases that are coming from the volcano to determine how close the magma is to the surface, said Driedger.
"Gases measured from the crater help predict the force of future eruptions." Driedger said the more gas that is trapped in the silicate rocks during an eruption the larger the explosion will be.
Mount Saint Helens erupted again during the years of 1989 through 2001 and 2004 through 2008. Those eruptions were not anywhere near the force of the eruption of 1980.
"The first eruption was very explosive," said Driedger. "The second eruption was relatively calm, like toothpaste squeezing out of a tube."
Driedger said volcanoes can erupt in a variety of ways. Driedger believes future eruptions will be less explosive than the one in 1980. "The eruption in 1980 collapsed the northern side of the volcano, so a future eruption won't be able to cause as large a landslide."
This photo of a steam blast eruption from the summit crater of Mount Saint Helens was taken on April 6, 1980, by James G. Moore.
The landslide caused by the collapse of the northern side of Mount Saint Helens in 1980 was the largest debris avalanche on Earth in recorded history, according to the USGS.
What does the future hold for Mount Saint Helens?
"We know magma is forming, we see little earthquakes, and we know it is reloading. We know it will erupt again and we know we may have as little as a week's notice. We have to be ready," Driedger said.
Torrential rain and strong thunderstorms pushed across the southern Plains on Saturday, spawning tornadoes and dangerous flash flooding from Kansas to Texas.
Lifeguards along the East and Gulf coasts are preparing to deal with one of the greatest beach dangers: rip currents.
A dangerous and life-threatening flooding situation will continue into Memorial Day, across portions of Texas, Oklahoma, Kansas, Arkansas and Missouri.
Showers and thunderstorms threaten to interfere with Memorial Day festivities across more than half of the United States.
Many areas in the Eastern states will have consistent summerlike heat and a buildup of humidity for the last week of May.
The second major tennis tournament of the year began on Sunday, as the world’s best tennis players begin their quest for the 2015 French Open title at Roland Garros in Paris.
West Coast (1982)
Heat wave: San Francisco, CA 91 degrees, (new record; previous record 79 in 1975) San Jose, CA 84 degrees Portland, OR 85 degrees (tied record)
North Texas (1986)
Severe thunderstorms produced 95 mph wind gusts and widespread damage. More than 3" of rain fell in less than an hour. A 29 year old women and 6 year old daughter drowned when the underpass they were driving into was flooded out.
Philadelphia, PA (1992)
A dramatic cold frontal passage. Early afternoon temperature over 80 degrees fell to a late-day reading in the 40s.