Unavoidable Cause
Bouvier's Law Dictionary and Concise Encyclopedia · John Bouvier; revised by Francis Rawle · 1914
Bouvier's Law Dictionary and Concise Encyclopedia
A cause which reasonably prudent and careful men under like circumstances do not and would not ordinarily anticipate, ami whose effects, under similar circumstances, they do not and would not ordinarily avoid.
Chicago, B. & Q. R. Co. v. U. S., 194 Fed. 342, 114 C. C. A. 334.