The Wireless Emergency Alerts system message was sent to phones across the Washington region Thursday morning. (Wireless Emergency Alerts System screengrab/Wireless Emergency Alerts System screengrab)

As expected, the quiet cacophony began just after 10 a.m. Thursday.

Phones, possibly millions of them across 20 Washington-area jurisdictions, beeped and buzzed in response to an emergency alert test issued by local emergency managers in coordination with the Metropolitan Washington Council of Governments.

The test of the Wireless Emergency Alerts system was meant to reach all cellphones in the region between 10 and 11 a.m. Officials estimated there would be about 5.2 million people in the area the alert was set to reach.

It was not immediately clear how successful the exercise was.

Sulayman Brown, Fairfax County’s assistant coordinator of the Office of Emergency Management and project manager for Thursday’s exercise, said the alert itself was only the first step.

“Now we need people to take our survey and answer some questions,” Brown said of a questionnaire being sent to community alert networks. “That will give us some good data to look at.”

Thursday’s test was the first of its kind in the D.C. area.

Although similar tests have been conducted over smaller areas — like on a piece of the Mall during President Trump’s inauguration — this was the first time the region attempted a coordinated message across many jurisdictions.

As it happens, there were hiccups.

Some people reported receiving multiple alerts, multiple times, while others said their phones did not make a peep.

Every jurisdiction was supposed to “push the button” at 10 a.m., Brown said, but some experienced a “technical issue” and did not get their alert out until nearly half an hour later.

Jermaine Washington’s phone lit up just after 10:15 a.m. at the end of the pasta aisle in a Largo, Md., grocery store.

“They’ve been doing this all day,” Washington said, pulling his phone out of his pocket to check the message. A few minutes later, the tone sounded again.

Next to him was Romelo Wood, who had not received a single notification.

“It feels kind of crazy,” Wood said about the possibility of being left out of the alert system in the event of actual danger.

Both men have the same mobile carrier. They were in the same place, pushing their carts up and down the same aisles. Neither could figure out why one phone buzzed and the other did not.

“It’s getting annoying,” Washington said as he pulled his phone out for the fifth or sixth time.

“It’s best to be annoyed,” Wood said. “At least you are in the know.”

Brown said those who received multiple alerts were likely experiencing what he called “locality bleedover,” meaning they had received notifications from various municipalities.

For instance, some Alexandria residents told Brown they received messages from their city as well as the District and Fairfax County.

Those who moved from one jurisdiction to another during the span of the one-hour exercise may have been subjected to multiple notifications.

The alerts were sent based on which cell tower a person’s phone connected to during the alert-system trial.

If you did not receive any message at all, Brown said, there could be a variety of explanations.

“Depending on where they are, as far as cell towers are concerned, it’s possible they were experiencing a slight overload of the system,” Brown said. “It could be the settings on their own phone or the type of phone they have. Androids and iPhones react differently.”

Brown said those who did not receive an alert should contact their cellular service provider and notify their local office of emergency management.

Surveys asking residents to report back on the effectiveness of the test were sent out starting at 11 a.m. Thursday by local community alert managers.

Residents have one week to provide feedback.

“We think it was a successful test,” Brown said. “Once we get all the data, we’re going to be able to improve on the emergency alert system. That was the purpose.”