Wireframes are crucial in web design as they serve as a visual blueprint for webpages, outlining the layout and functionality of each element. They help to map out the design before development, ensuring clarity and focus on user experience and navigation. By providing a structured representation of content placement and interactive components, wireframes facilitate communication among stakeholders, allowing designers, developers, and clients to align on expectations. This process minimizes the risk of costly changes during later stages by validating concepts early. Essentially, wireframes are foundational in creating effective web interfaces.