This section is from the book "The Law Of Contracts", by William Herbert Page. Also available from Amazon: Commercial Contracts: A Practical Guide to Deals, Contracts, Agreements and Promises.
The terms of the contract and the surrounding circumstances may show that one or the other party had agreed to assume certain risks; and in such case the happening of the event the risk of which has been assumed, does not amount to impossibility so as to discharge the liability of the party who assumed such risk.1 A contract to rebuild or to keep in repair is ordinarily so worded as to show the intention of the contractor to assume all risk of accident or destruction of the property which he has engaged to keep in repair or to rebuild, as the case may be;2 or to assume all risk due to defective plans.3 A contract to reconstruct a bridge if it is removed by any cause except fire, shows that the contractor intends to assume the risk of extreme flood;4 and he is bound to rebuild such bridge if it is destroyed by an unprecedented flood.1 A covenant that a bridge should remain safe for five years shows that the promisor assumes the risk of flood;8 and the contractor is liable if the bridge is destroyed by an unprecedented flood within such period.7
11 Hesser-Milton Renahan Coal Co. v. La Crosse Fuel Co., 114 Wis. 654, 90 N. W. 1094.
See also, Emack v. Hughes, 74 Vt. 382, 52 Atl. 1001.
12 See Sec. 2707.
1 England. Elliott v. Crutchley  A. C. 7.
United States. Berg v. Erickson, 234 Fed. 817, L. R. A. 1917A, 648.
Kentucky. Runyon v. Culver, 108 Ky. 43. L. R. A. 1916F, 3, 181 S. W. 640. Kansas. Cox v. Chase, 05 Kan. 531, L. R. A. 1915E, 590, 148 Pac. 765.
Indiana. Prather v. Latshaw, - Ind. -, 122 N. E. 721.
"Whether or not one, who by contract imposes upon himself an obligation or duty, is absolved from liability for his non-performance by a subsequent impossibility of performance caused, without his fault, by an act of God or an unavoidable accident, depends upon the true construction of his contract. The general rule is that one who makes a positive agreement to do a lawful act. is not absolved from liability for a failure to fulfil his covenant by a subsequent impossibility of performance, caused by an act of God, or an unavoidable accident, because he voluntarily contracts to perform it without any reservation or exception, which, if he desired, he could make in his agreement, thereby inducing the other contracting party, in consideration of his positive covenant, to enter into and become bound by the contract; and while courts may enforce, they may not avoid, such contracts in the absence of fraud or some similar defense. . . . But where it clearly appears, from the situation of the parties at the time they made their contract and from its terms, that they must have known that its performance would be impossible unless a person or persons, as in a contract of intermarriage, or in a contract for the personal service of an artist, such as a singer, should be living at the time for the performance of the contract, and there is no express or implied warranty of his life, a condition is implied that the contractor shall be absolved from liability if performance becomes impossible without his fault, by the death of the indispensable person. A like condition is implied in a contract for the delivery of a specific animal under like condition.
"There are authorities to the effect that, where it clearly appears from the situation of the parties and their contract, that they must have known when they made it that its performance would be impossible unless a thing, or a condition of things, then in existence, should exist at the time of perform-nace, or unless an indispensable thing or condition of things not then in existence should come into existence before and remain in-existence at the time of performance, there also, in the absence of an express or implied warranty of the existence of the indispensable thing or condition at the time of performance of the contract, without fault of the obligor, either by the act of God, or by an unavoidable accident, the obligor shall be absolved from liability for his failure to perform. . . . But no decision of the Supreme Court or of any Federal court to this effect has been cited or discovered which goes so far, and the rule adopted by the Supreme Court, which must prevail here, is otherwise.
The fact that the impossibility in question might have been foreseen readily, and that no provision is made against it, is regarded as sufficient to show that the party who made an unconditional and unqualified promise intended to assume the risk of the happening or event in question.8
"It is that, although general words, which can not be reasonably supposed to have been used with reference to the possibility of an event, may not be held to bind one, yet, where one, at the time of making his contract, must have known or could have reasonably anticipated, and in his contract could have guarded against, the possible happening of the event causing the impossibility of his performance, and nevertheless he makes an unqualified undertaking to perform, he must do so or pay the damages for his failure." Berg v. Erickson, 234 Fed. 817, L. R. A. 1917A, 648.
2 Alabama. Nave v. Berry, 22 Ala. 382; Warren v. Wagner, 75 Ala. 188, 51 Am. Rep. 446.
California. Polack v. Pioche, 33 Cal. 416, 95 Am. Dec. 115.
Connecticut. School District No. 1 v. Dauchy. 25 Conn. 530, 68 Am. Dec. 371.
Michigan. Van Wormer v. Crane, 51 Mich. 363, 47 Am. Rep 582, 16 X. W. 686.
Mississippi. Abby v. Billups, 35 Miss. 618, 72 Am. Dec. 143.
New York. Beach v. Crain, 2 N. V. 86, 49 Am. Dec. 369.
Pennsylvania. Hoy v. Holt, 91 Pa. St. 88, 36 Am. Rep. 639.
Virginia. Ross v. Overton, 3 Call. (Va.) 300, 2 Am. Dec. 552.
Texas. Miller v. Morris, 55 Tex. 412, 40 Am. Rep. 814.
3 Cameron-Hawn Realty Co. v. Albany, 207 N. Y. 377, 49 L. R. A. (N.S.) 922, 101 N. E. 162.
4 Mitchell v. Weston. 91 Miss. 414, 15 L. R. A. (X.S.) 833, 45 So. 571.
5 Mitchell v. Weston, 91 Miss. 414, 15 L. R. A. (X.S.) 833, 45 So. 571.
6 Meriwether v. Lowndes County, 89 Ala. 362. 7 So. 108.
7 Meriwether v. Lowndes County, 89 Ala. 362, 7 So. 198.