Prince William County police are encouraging residents to think about how they will protect their pets in the event of a disaster — and to tweet about it.

National Animal Disaster Preparedness Day is Thursday and is not the best-known holiday on the calendar. To raise awareness of the issue, the county police department has taken to Twitter.

Tweet a picture using the hashtag #petpared that proves you have taken action to ensure your pet’s safety in the event of an emergency, the department said, and they will retweet it from the police account on Thursday.

“When we say, ‘Prepare to be self-sustaining for 72 hours,’ we mean for animals, too. Just as they are planning for their clothing and their shelter and their food, they need to be planning for their animals,” said Fred Miller, a police captain and director of the county’s animal control bureau. “You may be self-sustaining for 72 hours, but you may not have thought about your dog or your cat.”

The department advises residents to prepare a kit containing enough pet food for three days, as well as prescriptions for any medication the pet requires in case he or she ends up far from home during an evacuation.

Police spokeswoman Sharon Richardson said Monday that few residents have taken part in the Twitter initiative. But preparedness can be difficult to photograph. A friendly call to a neighbor might not make for a compelling tweet, but it is among the department’s recommendations — residents should call their neighbors and ask if they will take responsibility for their pets if the owners find themselves away from home during a disaster, authorities said.

Police also said that pets should be microchipped so they can be relocated if they get lost, and vaccinated in case they end up housed among other animals in an emergency shelter.

Miller said that thanks to a Department of Homeland Security grant, the county has purchased a trailer of equipment that it can use to set up a shelter for pets in the event of an emergency such as a flood, when the county would house evacuated residents. The pet shelter would be in a separate wing of a public school where people were sheltered, and owners could visit their pets after they checked them in.

In the past, Miller said, concerns about their pets have prompted some residents not to evacuate, even when emergency management personnel tell them it would be advisable to leave. “People don’t want to leave their pets behind — a lot of times what has happened is they’ve chosen to stay. If their pets can’t go, they won’t go.”

Miller said even though the county has not yet had to put this plan into action, staff and volunteers run regular drills to practice setting up a pet shelter.