Despite the heavy rain yesterday evening, rainwater seemed under control at my house, so I thought, "I can safely leave the house for 1.5 hours of Zumba."
When I returned, water was running all over the basement. I immediately went to work.
It was disconcerting to bail water from the basin under the back porch. Despite using the powerful sump pump, the water level didn't go down for the longest time. Water was flowing into the basin nearly as fast as the powerful sump pump could evacuate it. After two hours of mopping, things seemed barely under control again.
I think I now understand one problem. Water is pooling next to the foundation in a place it never used to pool. I think the culprit is the tree. In the past, the water drained away, but during the drought years, the tree continued to grow and the base expanded, eventually blocking that drainage flow. Since it never rained enough in the drought years to be a problem, I never noticed before.