Heavy snow on the west coast made by the strongest wave...Seoul's first cold wave warning.

Snow clouds develop strongly as cold air passes through the warm West Sea

Upper flow stagnation...-Keep sending cold air below 40℃

The development of continental high pressure in the lower layers...Get the cold northwest wind out.

[Anchor]
This time, we will take a closer look at the causes of heavy snow on the west coast and the prospect of cold waves with a reporter.

Kim Min-kyung is in the YTN weather and disaster reporter studio.

First, let's look at the heavy snow situation.

How much snow did it fall in Chungnam and Honam?

[Reporter]
Yes, I prepared a radar image that can see the movement of snow clouds from yesterday afternoon until now.

Shall we look at the screen?

Snow clouds are constantly pouring into Chungnam and Honam from the northwest.

However, some of the snow cloud bands developed strongly, and some were mixed in a weak state, so depending on which cloud band came in, the snow poured strongly. I've repeatedly weakened.

Around 15cm of snow fell in Jeollabuk-do, including Sunchang and Buan, and 10cm in western Yeongnam, including Seocheon, Chungcheongnam-do and Hamyang, Gyeongsangnam-do.

[Anchor]
If so, I'm also curious about the cause.

Why do clouds continue to form in the West Sea?

[Reporter]
Yes, the biggest reason is that cold air enters our country through the relatively warm West Sea with the wind.

The larger the temperature difference between the air and the sea, the stronger the clouds develop.

Back then, because of the stagnant flow of the upper atmosphere, the low pressure cannot escape, and it keeps sending very cold air below minus 40 degrees Celsius down like a slide.

The cold air from the upper layer develops the cold continental high pressure near Siberia in the northwest in the lower atmosphere and continuously releases cold air to Korea.

Even in the lower layers, the air is so cold that the temperature difference with the sea widens by more than 30 degrees, and strong clouds are continuously formed.

[Anchor]
Last time it was in the metropolitan area, but this time the snow was concentrated in Chungnam and Honam, right?

[Reporter]
Correct.

In fact, the cause of heavy snow in the Seoul metropolitan area last November and this west coast is similar.

As the upper atmosphere flow stagnated, the upper cold air continued to descend to the lower layers, and the clouds developed as the cold air passed through the West Sea came in the same way.

The problem is 'Hanpa'. It wasn't cold in November.

So, the air in the lower atmosphere is still warm, but the cold air comes down from the upper layer and collides with the warm air, creating a low pressure.

The low pressure rotates counterclockwise, so there's no continuous northwest wind.

In November, heavy snow poured down in Gyeonggi-do, including Seoul, because the metropolitan area was the place where the low pressure with clouds passed.

This time, as the cold wave is added, the temperature is very low in the lower layers, so it's cold.

With cold air already in place, colder air comes down, so no low pressure is created, and snow clouds come in near Chungnam and Honam with the northwest wind.

The wind direction determines the area where snow falls.

Shall we look at the screen?

As of now, it has snowed for 24 hours.

It is concentrated only in Chungnam, Jeonbuk, and parts of Jeollanam-do.

Among the northwest winds, the wind came in the direction of Chungnam and Jeonbuk, so even in the same Honam area, there was no heavy snow in southern Jeollanam-do.

[Question4]
30cm more fall in Jeonbuk???

[Reporter]
Do you want to see the distribution of snow clouds expected by the day after tomorrow?

The purple color is snow clouds.

Snow clouds are expected in Chungnam and Honam until tomorrow night and the dawn of the day after tomorrow.

It's not like the snow is pouring out continuously and strongly.

I'm going to repeat the strength and weakness like now.

Yesterday's forecast predicted more than 30cm of snow in Jeonbuk by tomorrow.

With a lot of snow already falling, the new forecast is still more than 30cm in Jeonbuk, and more than 20cm in Gwangju, Jeonnam, and the west coast of Chungnam.

Although the time of snow has increased from tomorrow to the dawn of the day after tomorrow, it is expected that there will be more snow in the future than the amount that has been lowered so far.

In particular, it is expected that strong snow of 3 to 5cm per hour will be concentrated temporarily until tomorrow, so caution is needed.

[Anchor]
I'm worried that more snow is predicted after a lot of snow. This time, it's heavy snow again, right?

[Reporter]
Correct.

Since it is a snow cloud made in the West Sea, even if the temperature has fallen below zero, the nature of the snow is humid.

The snow itself is heavy, but the problem is that the accumulated snow freezes as it is because the temperature is low.

However, as the snow continues to fall, the snow covers the frozen area again, making it impossible to know where it is dangerous.

If you step on it thinking it won't be slippery because the snow is fluffy, there's a risk of slipping as it is if it's icy underneath it.

Be careful where the snow is piled up, and if possible, it is safe to move through a well-desorbed road.

[Anchor]
I also recognize the cold. It was quite cold today, but a stronger cold will come tomorrow?

[Reporter]
Yes, I previously looked at the cause of the heavy snow and told you that the upper atmosphere flow has stagnated, preventing low pressure from moving and continuing to send cold air down to the lower floors.

I'll also look at the diary on the upper floor.

Do you see two peanut-shaped red chunks in the north of the Korean Peninsula?

It is a low pressure containing cold air below minus 40 degrees Celsius that is stagnant in the upper floor.

The mass of low pressure on the left of this will come down to our country between tonight and tomorrow.

That's why tomorrow morning is the coldest, the coldest cold wave.

[Anchor]
As the cold wave warning was expanded and strengthened, the first cold wave warning was issued in Seoul this winter.

[Reporter]
Correct.

A cold wave warning was issued and then lifted in Gangwon-do and northeastern Gyeonggi-do, which were originally cold regions, but

Seoul was not issued because there was no big cold, but it was first lowered at 10 a.m. today.

This is because the standards for cold wave warnings are a little tricky.

First of all, the lowest temperature in the morning is expected to drop by more than 10 degrees from the previous day and be less than 3 degrees,
The second
is issued when the morning minimum temperature is expected to continue for more than two days with extreme cold below minus 12 degrees Celsius.

This is the matter of this cold wave special report.

The morning temperature in Seoul is expected to be minus 12 degrees Celsius tomorrow and the day after tomorrow, especially the wind chill tomorrow is expected to drop to minus 18 degrees Celsius.

[Anchor]
I think the cold will be incredible if the wind chill is minus 18 degrees, but isn't the wind chill different for each person?

[Reporter]
Correct.

People who get cold a lot are cold enough to tremble, but people with a high fever often pass it as if it were no big deal.

Each person has a different degree of feeling cold, so it is not possible to accurately measure the wind chill.

Do you want to see the graphic screen?

It looks very complicated.

It was developed in the United States and Canada in 2001, and it was created while studying how much wind takes away body temperature to reflect the cold that humans actually feel.

It calculates the wind chill by solving the equation with temperature and wind.

The wind ultimately determines the wind's perceived temperature, so the stronger the wind, the lower the perceived temperature, and in the absence of wind, the temperature and the perceived temperature are the same.

Usually, if the temperature goes down to around minus 20 degrees Celsius, you can think that it stings just by touching the bare skin.

[Anchor]
If it gets this cold, we are also concerned about the damage caused by cold waves such as freezing waves. Is there a way to prepare?

[Reporter]
Yes, in cold weather below minus 10 degrees Celsius, the water temperature in the water pipe also drops below 0 degrees Celsius, and there is a possibility of freezing.

When water freezes, the volume increases by more than 9% and the glass part of the meter can be broken.

To prevent freezing accidents, the inside of the measuring box must be filled with old clothes, cotton, and thermal insulation such as bubble wrap.

If you go out for a long time, you'd better leave the tap on low.

[Anchor]
Lastly, please point out the prospects for how long this cold wave will continue.

[Reporter]
Yes, I'll also look at the diary on the upper floor that I just saw.

The upper cold air mass comes down to our country tomorrow and gradually falls east.

Let's look at the situation the day after tomorrow, Friday morning.

Like this, the main air mass on the upper floor has escaped, but some cold air remains.

With the air already cold tomorrow, radiation cooling, in which heat escapes from the ground, will overlap overnight, and the bitter cold will continue until the morning after tomorrow.

After that, as the intensity of the cold gradually eases, normal temperatures are expected to recover after the weekend.