Assertion: thunderstorm's lightning | /r/CreatedBy | cumulonimbus clouds
Facets:
value: usually
type: TEMPORAL
Source sentences:
text: Lightning is usually produced by cumulonimbus clouds, which have bases that are typically 1–2 km (0.62–1.24 mi) above the ground and tops up to 15 km (9.3 mi) in height.