“disaster / calamity” in Japanese is 災, read sai, wazawa (さい, わざわ). It is a Grade 5 Kyōiku kanji, taught in year 5 of Japanese elementary school, and appears in words such as 災害 (disaster).
What does 災 mean?
火の災いを防ぐ。
Same sound, different character — the classic trap. Compare them side by side: