The Lake outside Lakeside Angels Psychiatric Hospital was connected to a long river that led to the ocean. In late January, low tide was in the morning. So after a failed attempt at searching the lake the previous day, Officer Grant and his team arrived the next day to search again.
However, a storm was forecasted for that day, so they only had a small window of time.
Note: Lakeside Angels Psychiatric Hospital doesn't actually exist, nor does the lake and the river. It is completely made up but I hope it sounds convincing enough haha.