At forty-six, she had learned to distinguish emergencies from the loud, administrative imitation of emergencies. A broken copier at the state office was not an emergency. A mayor calling to complain about the placement of a warning sign was not an emergency. A contractor asking her to sign an inspection certificate on a Friday afternoon because his investors were arriving on Monday was certainly not an emergency.

The call from dispatcher Tessa King had been different.

“Doctor Mercer, I’m sorry to wake you,” Tessa said at 3:08 a.m. “We’ve lost reliable readings from the western flood system. The river is coming up much faster than predicted. Our local team says everything is normal, but the county has three different numbers.”

Lena had sat up before the dispatcher finished speaking.

“Which station?”

“Gate Seven.”

She swung her feet to the floor.

“Tell the incident commander I’ll be there in forty minutes. Tell whoever is operating that gate not to make any changes until I can confirm what’s happening. And get me an actual water level from a person standing there. Not a screen.”

She dressed in the dim kitchen of her apartment outside the state capital. The rain made the windows look like sheets of hammered silver. Her teenage daughter, Nia, slept upstairs. On the refrigerator hung a crooked photograph of the two of them at a science fair, Nia grinning behind a homemade model of a suspension bridge.

Lena wrote a note beneath it: *Emergency call. I’m going to Briar Crossing. Grandma is okay as far as I know. Love you. Mom.*

Then she stopped and looked at the last sentence.

Her mother, Loretta Mercer, lived in Willow Court, an older apartment community just below the west drainage channel. Lena had spent years telling Loretta that the building was a bad place to stay during heavy storms. Loretta had spent those same years informing her that she had raised three children, survived two recessions, and did not require a daughter with an engineering degree to tell her how to listen to the weather.

Lena called. No answer.

She called again while putting on her boots. No answer.