roar, howl, growl, bellow
哮 centers on loud, forceful vocal outbursts: roaring, howling, growling, or bellowing, typically from an animal or a person in a fierce state.
哮 combines 口 (mouth) with 孝, which likely contributes the sound コウ. The character expresses loud vocal sounds made with the mouth.
A mouth 口 beside 孝 (which resembles a child 子 under an old person ⺹) suggests a fierce roar coming from the mouth, like a wild beast howling.
For コウ, imagine a fierce roar echoing through a cold, empty hall: the sound 'kou' (like 'co-') reverberates, matching the reading コウ.