Why does weather radar not reliably detect hail according to the text?

Weather radar often struggles to detect hail reliably because hailstones can scatter the radar pulse. When radar emits a signal, it relies on the reflection of that signal to detect various weather phenomena. Hail, due to its size and structure, can cause the radar waves to be scattered rather than reflected back directly to the radar system. This scattering effect diminishes the accuracy and reliability of hail detection.

In contrast to the other options, the strength of the radar pulse is typically sufficient for detecting various precipitation types, including larger objects. Hailstones, while they can vary in size, are often substantial enough to be detected by radar, and the capability of radar systems allows them to process the speed of detected objects, whether they are precipitation or other aerial phenomena. Therefore, scattering remains the primary reason for the ineffectiveness in reliably detecting hail through weather radar.