How does Les defend the possibility of a literal end-times blood river?
The literal blood river is defended by linking chapter 16's hundred-pound hail to armies packed into the Valley of Esdraelon. The hail crushes millions, then melts in Middle Eastern heat, producing blood deep enough for horses' bridles. A historical parallel is cited: after Wake Island, the Pacific was reportedly red for miles.
Les explains that the world's armies will be directed into the Valley of Esdraelon from every direction by a sovereign act of God, packed in almost senselessly. Then, in chapter 16, verse 21—the final plague and bowl judgment—hail falls on men, each stone weighing a talent, about 100 pounds. He notes that ordinary golf-ball or softball-sized hail can damage cars and roofs, but hundred-pound stones would crush everything. Because the Middle East is hot, the hail would not remain ice long; it would melt. With millions of men crushed in that valley, the result is a river of blood as deep as horses' bridles, which he takes as very literal. To avoid stretching the point, Les recalls reading that after the battle of Wake Island, when marines went in on the beaches and about 7,000 men were lost, the Pacific Ocean was red as much as two or three miles out from shore.