What typically causes small dimples or circular depressions on asphalt shingles?

Small dimples or circular depressions on asphalt shingles are typically caused by hailstones. When hail falls, it strikes the surface of the shingles with significant force, creating these indentations. This type of damage is often indicative of severe weather conditions, and the size and pattern of the dimples can help assess the strength and size of the hail that caused them.

Other factors like leaves, water pooling, or sun damage can affect asphalt shingles but do not typically result in the characteristic dimpled appearance associated with hail impacts. For example, leaves may cause staining or block drainage but wouldn't create indentations. Similarly, water pooling can lead to deterioration or leaks but doesn't create circular depressions. Lastly, sun damage usually results in fading or brittleness rather than physical impacts on the surface.