Baltimore City officials declared a Code Red Extreme Heat Alert for Wednesday with temperatures in the region expected to reach around 100 degrees and heat index, or “feels like” values, forecast to climb as high as 109 degrees.

“I urge residents — especially older adults, young children, people with pre-existing health conditions, first responders, and frontline workers — to stay hydrated, avoid strenuous outdoor activities, and seek relief in shaded or air-conditioned spaces whenever possible,” Mary Beth Haller, interim commissioner of health, said in a statement.

The Baltimore-Washington office of the National Weather Service has issued a heat advisory that’s in effect from 1-7 p.m. in the region. The advisory says heat index values of 105-109 degrees are expected.

Baltimore can expect temperatures to reach 92 degrees by 11 a.m. and peak at 101 degrees in the late afternoon, according to the latest hourly forecast from the National Weather Service.

Sinclair Lane Elementary School, Pimlico Elementary/Middle School and Arlington Elementary School in Baltimore will all be dismissed three hours early today, according to Baltimore City Public Schools, which cited forecast high temperatures and “mechanical issues” at those buildings.

The Baltimore Department of Public Works said Tuesday afternoon it may postpone or cancel some collection routes depending on how hot it gets Wednesday. Residents affected by a postponement Wednesday will get their trash collected Thursday, the department said.

Heat has been a dangerous and deadly force in Maryland this summer. More than 1,100 Marylanders have sought emergency medical care due to heat-related illness and 24 people in the state have died from heat-related illness, according to the latest available data from the Maryland Department of Health.

A Baltimore sanitation worker, Ronald Silver II, died while on the job from heat-related illness in early August. His family have called the death “completely preventable” and Gov. Wes Moore has called for a full investigation.

Silver’s death has, so far, also lead to an intense City Council hearing, which included criticism of Mayor Brandon Scott administration’s decision to hire a law firm to conduct a safety review for the Department of Public Works that has a history of lobbying against workplace safety rules, including proposed federal rules for heat safety.

Avoiding heat-related illness is all about prevention, according to the state health department.

General tips for safety include:

• Staying hydrated
• Reducing outdoor activity
• Staying inside between 11 a.m.-4 p.m.
• Seeking relief in air conditioning

Babies and children should never be left in a closed vehicle, even for a short period of time.

Heat cramps, heat exhaustion and heat stroke are all types of heat-related illness. Heat exhaustion happens when the body is unable to cool itself and can progress to heat stroke, which is a medical emergency, according to Johns Hopkins Medicine.