You don't say what size camera you are using.

I have hand held a 35mm with long telephoto at car races in the rain with a golf umbrella handle stuck down my shirt and caught under my belt. This was at the Grand Prix of Germany at Nurburgring about 1962, camping for three days of rain. People would approach laughing at the big red and white umbrella. As they got closer and saw I was dry and they were wet, they stopped laughing.

Today it is a little harder with the 7x17.

John Powers