A deadly heat wave is gripping the nation, prompting the Korea Centers for Disease Control and Prevention to activate a network of emergency medical facilities to take care of victims of heat stroke.

According to the centers, the sweltering heat has already left six people dead nationwide. Heat waves are often called a silent killer as people who die from heat exhaustion show few symptoms of illness.

Experts compare the ongoing heat wave to July 1994 when the temperature in Seoul stayed above 32 degrees Celsius on average. At the time, some 900 people, mostly elderly, died from the heat.

To avoid sunstroke, it is necessary to refrain from doing outdoor activities during the middle of the day and to drink plenty of water frequently.

The Korea Meteorological Administration has issued this year’s first heat-wave warnings in the southeastern city of Daegu and its surrounding areas in North Gyeongsang Province. Heat wave warnings are issued when the mercury is expected to reach 35 degrees Celsius for two consecutive days.

Daegu’s temperature reached 37 degrees Celsius yesterday, surpassing the 36 degrees Celsius marked Wednesday.

The weather agency has also extended the heat wave advisories from the southern part of the nation to the central region, which includes Seoul and the surrounding areas. It issues heat wave advisories when the temperature is expected to surge past 33 degrees Celsius for two days.

The hot weather has rekindled concerns about power shortages as people turn on the air conditioner to cool off. According to the Korea Power Exchange, electricity demand spiked at 73.14 million kilowatts at one point on Wednesday, pulling the power reserve rate down to 5 percent.

Power consumption reached a new high for three consecutive days this week as the sizzling heat continued. According to the KMA, the ongoing hot spell is expected to last for about 15 days. This means power shortages could get worse.

KPE officials need to monitor power demand and supply more attentively to avoid a repeat of the rolling blackout that the nation suffered last September. Citizens are also required to save electricity as much as possible by following conservation tips, such as unplugging appliances when they are not using them.

According to KPE officials, a real crisis could come in mid-August when factories go back into production after vacations. Corporations need to operate their plants flexibly to avoid peak hours.