Southwest Weather Research, Inc. v. Rounsaville

Brief Fact Summary.

Southwest Weather Research appealed a temporary injunction that prevented them from suppressing hail over Rounsaville’s property.

Synopsis of Rule of Law.

Landowners are entitled to the weather that occurs over their property.

Facts.

Southwest Weather Research (Southwest) flew planes that discharged a chemical substance to suppress hail and develop clouds. Rounsaville sued Southwest for trespass both for flying planes over his property and affecting the natural weather over his property. Rounsaville was granted a temporary injunction.

Issue.

Whether landowners are entitled to the weather that occurs over their property?

Held.

Yes. The injunction against Southwest is upheld. Southwest’s actions were a trespass to Rounsaville’s right to the air over his property.

Discussion.

Under ad coelum, everything above and below a landowner’s property belongs to the landowner. Improper use of airspace above a landowner’s property constitutes trespass.