Feb 28 (Reuters) - Snowflake forecast first-quarter product revenue below Wall Street estimates on Wednesday on expectations that customers would cut back on spending in an uncertain economy, sending its shares plunging more than 21% in extended trading.

The company appointed Sridhar Ramaswamy as its chief executive effective immediately, succeeding Frank Slootman who retired.

The company forecast current-quarter product revenue between $745 million and $750 million, below analysts' average estimates of $765 million, according to LSEG data. (Reporting by Jaspreet Singh in Bengaluru; Editing by Shailesh Kuber)