“Disasterous” or “disastrous”: which is correct?

Why people get it wrong

People often assume that the suffix -ous can be directly appended to certain words following a common English spelling pattern. While this is true for many words, such as dangerous or marvelous, the word disaster forms disastrous by dropping the e in its root before adding -ous. This irregular formation can cause confusion.

What kind of mistake it is

It is a spelling error.

Examples with disastrous

• The storm caused disastrous flooding throughout the region.
• Their investment turned out to be a disastrous mistake.
• Failing to back up the data had disastrous consequences for the company.