I've created another table on the Norgate Data web site that provides noteworthy irregular US Stock markets exchange halts/failures/issues (partial day), the time span of the issue, and the reason for the issue, which includes snowstorms, communications issues, software glitches, fires, electrical failures and paperwork issues, showing 40 such events: https://norgatedata.com/data-content-tables.php#noteworthy-halts-and-failures