The count from the headland

We carried the telescope to the end of the headland, where the sweep of open water usually made passing birds easy to follow. That morning, a bank of fog concealed the far side of the bay, while a strong crosswind shook the tripod whenever I tried to adjust it. We continued the count from memory, listening for calls and recording only the birds we could identify with confidence. I had thought that knowing the site well would be enough, but the familiar coastline had almost disappeared.

From the passage, select two words or phrases that describe weather conditions that made the bird count difficult.