I had a pretty spectacular wipe out while riding my gravel bike on the gravel Denali Hiway. Riding 700x40c Schwalbe marathon tires, pumped up to too much tire pressure for the conditions. I decided to change my line to the other tire track. Wheels went sideways and my bike and I got horizontal with the gravel. It was during an up and down, but probably the down, when I was going 12-15 mph. Probably due to maxing out the tire pressure, due to lack of experience. The surface doesn't cause the crash; it's your failure to adjust to the conditions.