In Texas, Sirens wailed on the Austin campus and cellphones pinged with text messages when the initial alert when out. Students described more confusion than panic as they exited the sprawling campus, where police blocked off all roads heading in as lines of cars sat in gridlock trying to get out.
The evacuation also created logistical concerns for the 14th-ranked Texas Longhorns football team. Inside a police station across from the football stadium, executive senior associate athletics director Ed Goble asked about getting the athletics complex building cleared because the team had to leave for a Saturday game at the University of Mississippi. The team's locker room is inside the building.
Goble later said he wasn't asking that the team be made a priority. Shortly after 11 a.m., while the rest of campus remained almost deserted, Goble said police had given players permission to go into the athletic complex to pack for the game.
"All building managers are notified at the same time and all are expected to move as rapidly as possible," said Gary Susswein, spokesman for the UT president's office, noting there was no priorities list for what buildings were to be cleared first.
With rain falling, students stood under awnings and overhangs and inundated nearby off-campus restaurants and coffee shops as they waited for updates.
Abby Johnston, a production and special editions coordinator for Texas Student Media, said she received the first text message from the university while thinking about what she would publish in the next day's paper. Then the sirens blared.
"We do the siren test once a month and so at first people thought maybe it was just a test, and then we started to tell everybody, `No actually we have to get out of here pretty immediately,'" said Johnston, 22. "There was definitely a little bit of nervous tension."
Tania Lara, a graduate student at the Lyndon B. Johnson School of Public Affairs, said she was at work inside a central campus academic building when she got a text message to get as far away was possible.
"It was calm but nobody knew what was going on," she said, describing a crush of students heading for the exits. "No one was yelling `get out of here' or anything like that."
Also Friday, Valparaiso University in Indiana increased security and posted a warning to students on its website after a vague threat was discovered scrawled in graffiti. The school said the threat claimed "dangerous and criminal activity" would occur during the university's daily chapel break.
The FBI and local authorities searched the campus but found nothing suspicious and university spokeswoman Nicole Niemi said classes and other regular activities would go on.
Associated Press writers Will Weissert in Austin, Ramit Plushnick-Masti in Houston, Nomaan Merchant in Dallas; Paul J. Weber in San Antonio; Dave Kolpack in Fargo, N.D.; and Ashley M. Heher in Chicago contributed to this report.