The article.

Aircraft can accidentally punch holes in clouds, leaving a trail
of snow or rain in their wake, a new study finds.

Turboprop and jet aircraft that climb or descend under certain atmospheric
conditions can inadvertently trigger what's known as cloud seeding. This
technology is usually associated with schemes to control the weather. However,
cloud seeding can happen by accident as planes soaring through mid-level clouds
leave behind odd-shaped holes or channels in the clouds and cause narrow bands
of snow or rain to develop and fall to the ground.