Denver’s outdoor warning sirens will sound for three minutes on Wednesday morning as officials test the city’s emergency systems.

All 86 outdoor sirens are scheduled to go off at 11 a.m., and at the same time the wireless emergency alert system will send a test text message to all mobile phones in Denver.

People in neighboring counties may also receive the emergency alert message, the Denver Office of Emergency Management said in a statement.

“Speed and clarity are critical in an emergency,” Executive Director Matthew Mueller said in a statement. “This test helps ensure Denver can deliver alerts across multiple platforms, so people know what to do right away.”

Craig Morton, who spent 18 years in the NFL and became the first quarterback to start the Super Bowl for two franchises — the Dallas Cowboys and Denver Broncos — has died. He was 83.

Morton died Saturday in Mill Valley, California, the Broncos confirmed through his family.

Morton is one of only four QBs to start the NFL’s biggest game with two organizations. The other three — Peyton Manning, Tom Brady and Kurt Warner — all ended up with at least one win. Morton’s only Super Bowl ring came as a backup.

His first Super Bowl start was in a turnover-plagued Super Bowl V to end the 1970 season — a 16-13 loss by the Cowboys to the Colts. Morton threw the Cowboys’ first touchdown pass in a title game.

Seven years later, and after an unsuccessful stint with the New York Giants, Morton led the Broncos to a matchup against his former team. He threw for 39 yards and four interceptions before getting pulled for Norris Weese in a 27-10 loss, which marked the first of four straight Super Bowl defeats for Denver.

Known for his strong arm, Morton turned in a college football Hall of Fame career at California, where he played for coach Marv Levy and assistant Bill Walsh. Morton went fifth in the 1965 NFL draft to the Cowboys. Oakland also took him in the 10th round of the AFL draft.

He joined a Cowboys team coached by Tom Landry that had veteran Don Meredith at QB. Morton played in four games that season. He then split time with up-and-coming Roger Staubach in 1970-71, the year the Cowboys went to their first Super Bowl.

The next season, Morton and Staubach also split time — at some points, even alternating every play. But ultimately, it was Staubach who took over the starting job, then led the Cowboys to the Super Bowl and a 24-3 win over Miami. Staubach was the MVP of that game and it wasn’t hard to imagine the end of Morton’s time in Dallas.

The Cowboys dealt their backup to the Giants in 1974 for a package that included a pick Dallas would use to take defensive lineman Randy White, who became a Super Bowl MVP and Pro Football Hall of Famer.

Morton struggled in New York, but enjoyed a renaissance after getting traded to Denver before the 1977 season — the season that put the Broncos on the map.

The veteran QB became the final piece for a Broncos team under a new coach, Red Miller, who inherited a strong defense that would become known as the Orange Crush.

Morton led the Broncos to a 12-2 record and playoff wins over the Steelers and Raiders. He famously spent the week in the hospital with a hip injury before spearheading the win over rival Oakland.

Four years later — and after the Broncos had toyed unsuccessfully with finding his replacement — Morton teamed with a new coach, his former Cowboys teammate Dan Reeves. In 1981, Morton threw for 3,195 yards and 21 TDs, both career highs (he matched his best mark in TDs).

He retired after starting three games in the strike-shortened 1982 season. Denver would trade for John Elway, who supplanted Morton as the franchise’s most famous and revered No. 7.

Morton threw for 27,908 yards over his career with 183 touchdowns and 187 interceptions. Morton ranked in the top 20 all-time in yards passing and TD passes when he retired following the 1982 season.

He was voted into the Broncos’ Ring of Fame in 1988, along with two other standouts from that ’77 team — Haven Moses and Jim Turner.