Were the force of the winds foreseeable?
If I build a big tower of bricks and a gentle breeze, an act of God, wafts by and knocks down the poorly-built tower unto cubo's abode, the act of God defense is not going to fly. We can reasonably predict some things that would colloquially be defined as an act of God. The Sun will come up tomorrow, the wind will blow, and, water is wet come to mind. That does not mean a person doesn't lose the ability to successfully sue if hurt by the person who built a big magnifying glass at night, redirected drainage to the hospital ER, or failed to properly secure a trampoline.
Describing the concept, Burford v. Village of La Grange, 234 NE 2d 120 - Ill: Appellate Court, 1st Dist. 1967 used a PA case in the discussion:
In Carlson v. A. & P. Corrugated Box Corp., 364 Pa 216, 72 A2d 290 (1950), the Supreme Court of Pennsylvania stated:
"... a unanimous host of authorities, both in our own Commonwealth and elsewhere, ... uniformly hold that although no liability can be fastened upon the defendant if the damage is caused by an act of God so overwhelming as of its own force to produce the injury independently of the defendant's negligence, such liability does arise if the damage results from the concurrence of the defendant's negligence with the act of God and the damage would not have occurred in the absence of such negligence."
Perkinson v. Pollution Control Board, 543 NE 2d 901 - Ill: Appellate Court, 3rd Dist. 1989 described it further:
A similar holding is found in Freeman Coal Mining Corp. v. Pollution Control Board (1974), 21 Ill. App.3d 157, 313 N.E.2d 616, another case where water pollution occurred when rainwater seeped through a mine refuse pile. Again, the court ruled that the fact that pollution came from the seepage off the owner's land was sufficient proof that the owner allowed the discharge within the meaning of the statute. It was no defense that the discharges were accidental and not intentional or that they were the result of an "Act of God" (rain) beyond its control. The court relied in part upon a case from another jurisdiction which held that the legislature had imposed a duty to take all prudent measures to prevent pollution.
We could get to the modern use of the common-law term in Salvi v. VILLAGE OF LAKE ZURICH, 2016 IL App (2d) 150249 - Ill: Appellate Court, 2nd Dist. 2016:
Perhaps "act of God" was a reference to the common-law doctrine of that name. "`A loss or injury is due to the act of God[] when it is occasioned exclusively by natural causes such as could not be prevented by human care, skill[,] and foresight.'" Evans v. Brown, 399 Ill. App. 3d 238, 246 (2010) (quoting Wald v. Pittsburgh, Cincinnati, Chicago & St. Louis R.R. Co., 162 Ill. 545, 551 (1896)). "[L]iability is only precluded if the alleged act of God constitutes the sole and proximate cause of the injuries." (Emphasis added.) Id. Plaintiff alleged that the Pond overflowed following "heavy" rains, but whether the rain was the "sole and proximate" cause of the alleged injuries is a question of fact inappropriate for resolution at this stage in the proceedings.
If the trampoline had flown off the neighbors property and damaged cubo's property in the past, that is a step towards duty to deal with that in similar situations. Just because a storm has powerful winds does not relieve a person of liability if those winds were predictable and the damage could have been prevented with a couple of stakes or sand bags on the legs of the trampoline.
