"an emergency plan" is correct and usable in written English.
For example, "The school administrator developed an emergency plan in case of a natural disaster."
Create an emergency plan.
As an alternative to blackout, the government instituted an emergency plan aimed at reducing electricity consumption.
If not, he said an emergency plan calls for trucking in water.
"You should sit down with your family and come up with an emergency plan.
It must have been part of an emergency plan because they moved so quickly.
Murray presented an emergency plan to Perry in March 2017, days after Perry became energy secretary.
But Uefa officials do have an emergency plan B to transfer Ukraine's games to Poland.
The wounded were distributed smoothly across at least five city hospitals, with an emergency plan activated.
It is also important to devise an emergency plan for unexpected situations, according to terminal illness charity Marie Curie.
The defence minister said an emergency plan was now underway to cover the entire country with Iron Dome capacity.
A billboard on I-95 in Connecticut asks, "Does your family have an emergency plan?" Er, no.
