It sounds like "strands" is being used as a verb. Mud strands vehicles. It causes them to become stranded.

When you are asking a question about a news story, it is helpful to mention what the story was about. I am guessing you are reading about the Burning Man event in the US. To "strand" can mean to leave someone isolated and stuck, with no way to leave. Here are some ways in which the event has been reported: "Foot-deep mud at Burning Man strands thousands in Nevada desert; 1 death reported." Here, it is clear that "mud" is the subject. What is the mud doing? "Stranding." What did the mud strand? "Thousands" (of people). "Heavy Rain Strands Thousands at Burning Man Festival. Heavy downpours turned the Burning Man festival grounds into thick mud, limiting access..." And here is one, from USA Today, with the exact phrase "mud strands:" "Clear skies expected to aid 'exodus' after rain, mud strands thousands." Again, "mud" is the subject. What did it do? It "stranded thousands." Why "strands" and not "stranded?" This is the "historical present," using the present tense to express the past. This happens in Spanish, too: "Cristóbal Colón descubre América en 1492" (instead of "discubrió")

BACKGROUND: "strand" can be a verb, "TO strand." It can also be a noun, "A strand." A strand is a beach (playa). Some things, such as boats, can only travel on water. Sometimes, when the water level is high, wind can blow a boat high up onto the beach. Then the water falls. The boat is on the dry beach. It cannot move. It is "stranded" in the original, literal sense. It is on the strand. It cannot get off. By extension, you are "stranded" when you have traveled to an isolated place, and your car breaks down, or your plans for returning fail. For example, you might say: "In 1980, I flew to Seattle in 1980. Then a volcano, Mt. St Helens erupted. There was so much dust that all flights were cancelled. I couldn't leave Seattle. I was stranded in Seattle for days." "Stranded" and "to strand" are common in both US and British English US English. The noun, "a strand" very is rare in US English.