High temperatures in the lower 90s and high humidity made it feel like 100 to 110 degrees in the Twin Cities Monday.
The oppressive conditions will hang around a bit longer than first thought, so the National Weather Service extended an excessive heat warning for the overnight hours as well. It now expires Tuesday at 7 a.m.
Meanwhile, a heat advisory is in effect across the rest of central and southern Minnesota and far western Wisconsin.
Air temperatures around the state reached the upper 80s and low 90s, even in northern Minnesota; it reached 89 degrees Thief River Falls and Grand Rapids Monday.
Steamy conditions could help fuel storms Monday night, the National Weather Service said. Damaging wind is the main threat, the weather service says in a severe weather outlook.
The service called for a moderate risk of severe storms in much of northern and central Minnesota, and a slight risk in much of the rest of the state.
The NWS has the latest warnings on its website, and the information is updated in real time.
Here's the link for northwestern Minnesota and eastern North Dakota.
Here's the link for northeast Minnesota and northern Wisconsin.
Here's the link for the Twin Cities metro area and southern Minnesota.
A heat advisory means there is a heightened risk of heat-related stress and illness, especially for the very young and elderly, those working in the heat, and those without air-conditioning, the weather service notes.
Forecasters say it'll be slightly cooler Tuesday in the metro, with a high of about 87 degrees. The high will be about 80 degrees the rest of the week, the weather service says.
Heat safety tips
In a year that's been colder than normal, Monday marks summer's first significant wave of heat this year. Some may not be acclimated to the high temperatures expected for the next few days, the National Weather Service says.
The weather service says it's important to know the symptoms of heat exhaustion and heat stroke. The Mayo Clinic says heat exhaustion is preventable, but can lead to heat stroke if proper steps aren't taken.
Signs and symptoms of heat exhaustion may develop suddenly or over time, especially with prolonged periods of exercise. Possible symptoms include: Cool, moist skin with goose bumps when in the heat, heavy sweating, faintness, dizziness, fatigue, a week, rapid pulse, low blood pressure upon standing, muscle cramps, nausea and headache, Mayo says.
If you think you are experiencing heat exhaustion, it's important to stop all activity and rest, move to a cooler place and drink cool water or sports drinks. If symptoms worsen or don't improve within an hour, contact a doctor, Mayo says.
Heat stroke, which is the most serious form of heat injury, can occur when a person's body temperature rises to 104 degrees or higher, the Mayo Clinic says. If heat stroke is left untreated, it can quickly damage a person's brain, heart, kidneys and muscles. The damage to those organs worsens the longer treatment is delayed, which can increase the risk of serious complications or death, Mayo says.
Symptoms of heat stroke:
– High body temperature: 104 degrees or higher is the main sign of heat stroke.
– Altered mental state or behavior: Confusion, agitation, slurred speech, irritability, delirium, seizures and coma can all result from heat stroke.
– Alteration in sweating: In heat stroke brought on by hot weather, a person's skin will feel hot and dry to the touch. However in heat stroke brought on by strenuous exercise, skin may feel moist.
– Nausea and vomiting, or feeling sick to the stomach.
– Flushed skin: Skin may turn red as a person's body temperature increases.
– Rapid breathing: Breathing may become rapid and shallow.
– Racing heart rate: A person's pulse may significantly increase because heat stress places a burden on the heart to help cool the body.
If you are showing signs of heat stroke, the Mayo Clinic advises you to call 911. It's important to take immediate action while waiting for emergency treatment. Do so by getting into shade or indoors, remove excess clothing, and get cool with whatever is available, like a cool tub or shower or garden hose, Mayo says.
To prevent heat exhaustion and heat stroke, officials urge people to take extra precautions if they work or spend time outside, and if possible reschedule strenuous activities to the early morning or evening, when temperatures won't be as hot.
It's important to wear lightweight, loose-fitting clothing and drink plenty of water if working outdoors, and take frequent rest breaks in shaded or air-conditioned areas.
The weather service also recommends checking up on relatives and elderly neighbors who may be more susceptible to heat-related illnesses.
The Minnesota Department of Health says heat-related illness accounted for 44 deaths in Minnesota from 2000-2012, with 19 of those deaths occurring in 2001. For those years, the month of July has had the highest number of heat-related deaths, with 23.
The state Department of Health notes that deaths directly related to heat are not common in Minnesota and often are unidentified, which leads to an underestimation of heat-related deaths.