Has there been an earthquake? Was the ground shaking so much that it was difficult to stand? If the answer is yes to both, then it's time to get to higher ground.
That's what happened Saturday evening as a magnitude-7.7 earthquake struck just offshore and shook Haida Gwaii and a large stretch of coastal British Columbia.
It was the only tsunami warning Kendall, the emergency co-ordinator for Skidegate, needed before she and other local emergency officials mobilized an evacuation.
"Anything that's hard to stand up in for more than a minute, you go to higher ground," Kendall said in an interview, adding that many in her community came to the same conclusion on their own.
"By the time we got to the firehall, 15 minutes after the earthquake, there was already steady streams of cars going up to the high ground. People went and grabbed all the elders, their relatives."
The weekend earthquake has prompted scrutiny of how the provincial government handled the quake, with emergency co-ordinators in some municipalities complaining that it took as long as an hour before they heard anything official.
It has also revealed the challenges facing local and regional governments when it comes to communicating those warnings to the public, with some citizens glued to social media and others, like some in Haida Gwaii, living in remote areas without telephone service.
Another earthquake also rattled the area Monday night, striking at 7:49 p.m. with a magnitude-6.2 and at a depth of nine kilometres, according to the U.S. Geological Survey.
Officials have said they expected aftershocks from Saturday's quake to continue for several days. One on Sunday had a magnitude of 6.4
Kendall said she didn't receive anything directly from the government for about an hour Saturday night, but she called the provincial emergency program herself a few minutes after the earthquake and was told there was a tsunami warning.
Officials in some communities, such as Prince Rupert on the mainland, said they received word from the province within 10 or 15 minutes of the quake.
Others, including several on Haida Gwaii, said they didn't hear anything for about an hour, but they all pointed out their emergency plans take effect as soon as the ground starts to move.
"There was a delay," said Carol Kulesha, the mayor of the Village of Queen Charlotte.
"But we didn't depend on that. We got notification directly from the source. We understand we're remote and that no one is going to come in the beginning to take care of us. We just put our plan into effect."
Debate about the province's response prompted Justice Minister Shirley Bond, whose ministry oversees disaster response, to announce on Sunday there would be a full review of what happened.
The earthquake occurred a few minutes after 8 p.m. on Saturday, though the first B.C. government media bulletin warning of a tsunami wasn't issued until about 9:05. Meanwhile, the first mention of the warning on the official Emergency Info BC Twitter account wasn't posted until 8:55.
Chris Duffy, executive director of operations with Emergency Management BC, said his office sent out initial details about the tsunami warning 12 minutes after the quake in an email that went to various communities and agencies.
He couldn't explain why some officials said they didn't receive word for an hour, but he said the quick response on the ground suggested people had enough information to act.
"Their first notification was from Mother Nature and that was when the ground shook violently," Duffy told reporters during a conference call.
"To say that folks on Haida Gwaii didn't get information and didn't get contact is not quite a fair characterization of what occurred. They had the initial ground shake and took action. They certainly had contact from my staff within minutes."
Duffy added that many local emergency personnel, as well as news outlets, would have received a warning from the West Coast and Alaska Tsunami Warning Center a few minutes after the quake.
The actual responses in each community varied, depending on the resources available and the people living there.
There is only one tsunami siren on Haida Gwaii, located in the community of Massat. It was blaring a warning almost immediately after the earthquake.
In communities such as Queen Charlotte, which is waiting for a new tsunami siren to be delivered, police cruisers drove around using their loudspeakers to warn residents.
Tow Hill Road, a tiny community on the north end of Haida Gwaii, has an automated phone system to call residents in an emergency, but emergency co-ordinator Chris Ashurst said telephone numbers become out of date and some residents don't even have phones.
"We do rely on people checking on their neighbours," said Ashurst.
"We'll use any tool we can out here. If it's driving up people's driveways and banging on the door, then that's what we use."
None of the communities in the immediate vicinity of the quake appeared to rely on social media to get the word out. Emergency Info BC was mocked on Twitter by users complaining about the dearth of information, which prompted whoever was overseeing the agency's account to write: "We do not compete with media (or Twitter)."
Andrew Sachs of Witt Associates, a Washington, D.C.-based company that specializes in emergency preparedness, said social media and mobile technology are fast becoming powerful tools to get information out during a potential disaster.
"You can actually provide visual messages and you can actually choose, based upon where a cellphone is located, what type of messaging goes out," Sachs said in an interview.
But Sachs acknowledged such technology has limitations, notably that many demographics aren't plugged in to social media.
"All of these tools are partial solutions," he said.
"You're unlikely to get a substantial hit among seniors 65 and older from tweeting, but for people 30 and under, that may be one of the best tools available to reach them. The people who receive those tweets often begin to pass that message along, using not only social media but also more traditional forms of communication."