LOS ANGELES — That loud whooshing sound you heard in the predawn hours Tuesday may have been Hollywood exhaling, after negotiators for the studios and networks and the Writers Guild of America reached an 11th-hour deal to avert what would have been the industry’s first major strike in a decade.

The tentative agreement was forged not only under the pressure of the WGA’s threat of a walkout by its roughly 13,000 members, but also in a television and film production landscape redrawn by the emergence of nontraditional producers and platforms, including Netflix, Hulu and Amazon.