A more thorough explanation:

A mass layoff is when a company lets go of a large number of employees at once. The Worker Adjustment and Retraining Notification Act (WARN Act) requires employers with 100 or more full-time employees to give their workers 60 days' notice before a mass layoff. This notice is also required for any layoff that affects 500 or more workers, or 50 or more workers who represent at least one-third of the workforce.

Example 1: An employer announces a seasonal layoff that will happen on a certain date. Later, they send a letter to the laid-off workers clarifying possible employment opportunities with another company. This combination of letters provides adequate notice under the WARN Act. (Kalwaytis v. Preferred Meal Systems, Inc)

Example 2: An employer provides a written notice to all employees before a mass layoff, even if not all employees are affected. This notice meets the requirements of the WARN Act. (Snider v. Commercial Financial Services)

These examples show that employers must follow the WARN Act and provide adequate notice to their workers before a mass layoff. This gives employees time to prepare for the layoff and look for new job opportunities.