Updated

Thousands of tourists spent hours gazing at Mount St. Helens (search), packing buildings, crowding parking lots and watching from roadsides to see what the rumbling mountain would do next.

While scientists kept a watchful eye on the volcano (search), throngs of curious onlookers filled the mountain's visitor centers. Others sat outside in lawn chairs, sipping coffee, determined to witness the next eruption.

Joy Parker, 52, peered at the volcano for more than six hours Saturday, staring at it until her eyes blurred.

"I just know if I left, it would go off," Parker said. "She's going to go when she feels like it and not just when I'm waiting for it."

Geologists said powerful tremors and a blast of steam Saturday indicated an eruption could be imminent, prompting officials to raise the volcano's alert level and clear hundreds of visitors from the area.

Some tourists were disappointed when officials widened a safety zone around the mountain to seven miles and closed the building closest to the volcano, the Johnston Ridge Observatory (search), five miles away. Some people relocated several miles north to the Coldwater Ridge Visitors Center, which officials said was safe.

Todd Cullings, assistant director of two visitor centers, spent the day patiently explaining that volcanos follow their own schedule.

"People and volcanos operate under different time frames. Volcanos are on their own time. We get these big surges and then we get lulls. It's all part of it," Cullings said.

Cullings was mindful of the danger, recalling that 57 people were killed when the volcano erupted with devastating force on May 18, 1980. "We don't want anyone to die or be injured in this eruption," he said.

Ken Feist, 39, got up early to drive to the mountain from his home in Olympia. He arrived in time to see a midday steam eruption and was later among thousands of people evacuated from Johnston Ridge.

"Everyone was bummed out. One woman was shrieking, 'Run for your life.' A lot of people were more angry than anything," Feist said.

Feist said he felt safer after evacuating, though he was still nervous about sitting outside the safety zone in sight of the crater.

"There's a curiosity, but to tell you the truth, I'm not sure I'd want to be here if it did blow," he said. "It's a little scary."