With 2,340 games scheduled from early spring to late summer every year, Major League Baseball is not unfamiliar with encountering challenging weather during its season.
Seven out of 30 MLB teams have roofs covering their field of play and six of those teams have stadiums with retractable roofs, so fans in those cities can head to the ballpark without fear of games being canceled. For the 23 other stadiums across the U.S., weather can become more of a concern, not just for postponements, but for the safety of spectators as well.
In 2012, Coors Field, home to the Colorado Rockies in Denver, Colorado, became the fourth MLB stadium designated as StormReady by the National Weather Service. According to a press release from the National Oceanic and Atmospheric Administration, Rockies officials worked with the NWS and local emergency management to "adopt a rigorous set of detection and warning criteria to provide protection from severe weather."
It's a partnership that the Rockies still rely on heavily today, according to Vice President of Ballpark Operations Kevin Kahn.
"Severe weather is something that we deal with in one form or another, just about every season," Kahn said. "So whether it's heavy rain and wind, or hail or lightning or even tornadoes, it's something we deal with quite a bit."
According to the NWS, StormReady is a voluntary program designed to better prepare communities for the effects of extreme weather-related events. To date, there are more than 2,300 StormReady sites across the country.
As is the case with many teams around MLB, the Rockies contract a private meteorologist to give them weather information. The meteorologist gives the Rockies daily morning weather updates and if the organization is in game mode, Kahn said they have access to him via telephone and occasionally in person at the stadium.
Prior to the beginning of the game, control of when the game starts is up to the home club. Once the first pitch is thrown, the game is in the hands of the four-man umpire crew, specifically the crew chief. From that point on, the Rockies' head groundskeeper, in coordination with the meteorologist, will inform the crew chief of pertinent developments.
In addition to working with a meteorologist, the Rockies utilize a weather radio in the team's command center so they can receive up-to-date information on storm watches and warnings. Designated shelters and pre-scripted public address announcements are two other vital components of the team's severe weather strategy.
"If we have lightning that comes through then we clear our upper deck, so we have announcements and operational plans with our staff to facilitate that," Kahn said.
Once a weather delay is in effect, how quickly a game resumes depends on the forecast, Kahn said, adding that stoppages usually last a minimum of 30 to 45 minutes. In some cases, delays will last several hours if it's a case where two teams aren't scheduled to play one another again, and there are limited open dates for rescheduling.
Other times, if the schedule allows, games can be suspended and finished on a separate date, typically when the clubs begin another series.
"You really want to make every effort, with obviously player and fan safety being the paramount determining factor, but you always try to get a game in because it is difficult to reschedule, although certainly it's been done," he said.
For Heather Nabozny, head groundskeeper of the Detroit Tigers, the weather forecast is the first thing she checks in the morning and the last before she goes to bed.
During severe weather situations, Nabozny is the primary go-to person for the umpires, who rely on her for the forecast, then decide when to remove the players from the field.
"We play until we can't play anymore, or if there's lightning in the area," she said.
If storms are impending prior to the beginning of the game, Nabozny, who is in her 17th season as head groundskeeper, said it's nice to be able to tarp the field before the rain arrives, because it can be difficult to get the tarp down if there are gusty winds ahead of the storm.
The team is cautious about removing the tarp until the rain has finally moved out of the area. Pitchers need at least 30 minutes to warm up, and recovering the field or bullpen mounds if it starts raining again can alter their pregame routine.
"You don't want to start up a pitcher and have them stop, shut down, because then you've burned the pitcher and they can't be used for the game," she said.
Even when the Tigers are on a road trip, the grounds crew has to constantly keep the field ready for other events, such as college baseball games or concerts. Many aspects of the weather, such as humidity, moisture and wind, affect much of what the grounds crew does, whether it's trying to grow grass or keeping the infield clay moist.
"We still have to keep the field in playing condition, like we would when the team is here," Nabozny said.
During her tenure, Nabozny said there has been times when storms have developed overhead, but she and the rest of her staff were ready. She said if there are real volatile conditions, her staff watches the skies constantly and keeps in touch with the Tigers' contracted meteorologist.
Sometimes, however, having a retractable roof can still not ensure protection against weather that can be difficult to predict. On April 6, the Miami Marlins experienced the first weather delay in the four-year history of Marlins Park, after the roof was left open and showers moved over the stadium.