With large-scale sandstorms approaching, how are sandstorms classified? What are the criteria for issuing sandstorm warnings?

Whenever the weather turns warmer, some relatively uncommon weather symbols will appear in the weather forecast. For example, did you find them in the weather forecast program on the evening of March 14?

So the question is, the symbols in the figure

What does it mean?

I believe that many people’s first impression is: Isn’t this the US dollar? Is it going to rain money from the sky?

Editor: It would be nice if it were true...

In fact, this is the dust storm icon in the weather forecast. It has several brothers that look a bit similar. Do you recognize them?

Like the dust icons, these also represent different levels of sandstorm weather.

Sandstorm weather refers to a weather phenomenon in which sand and dust are suspended in the air, making the air turbid and reducing visibility.

According to horizontal visibility and wind speed, we can classify sandstorm weather into different levels, in order:

Floating dust - there is no wind or the wind force is ≤ Level 3, sand and dust float in the air, making the air turbid, and the horizontal visibility is less than 10km.

Blowing sand - the wind blows up sand and dust on the ground, making the air quite turbid, and the horizontal visibility is within 1km~10km.

Sandstorm - wind blows up sand and dust from the ground, making the air very turbid and the horizontal visibility <1km.

Severe sandstorm: wind blows up sand and dust from the ground, making the air very turbid and the horizontal visibility <500m.

In addition, there were extremely strong sandstorms.

There are three different warnings based on indicators such as the level and range of sand and dust:

01 Blue Warning : It is predicted that in the next 24 hours, parts of more than three provinces (autonomous regions, municipalities) will experience blowing sand or dust weather, or it has already occurred and may continue.

Figure/ Weather forecast for February 19, 2024

02 Yellow Warning : It is predicted that sandstorms will occur in large areas (more than 5 county-level administrative regions) in more than 3 provinces (autonomous regions, municipalities) in the next 24 hours, or have already occurred and may continue.

Figure/ Weather forecast for March 22, 2023

03 Orange warning : It is predicted that in the next 24 hours, strong sandstorms will occur in large areas (more than 5 county-level administrative regions) in more than 3 provinces (autonomous regions, municipalities), or have already occurred and may continue.

△Source: "Central Meteorological Observatory Meteorological Disaster Warning Release Method"

It is extremely rare for the Central Meteorological Observatory to issue an orange sandstorm warning. Even I, a knowledgeable editor, have never seen it.

As March approaches, the number of sandstorms affecting our country will gradually increase.

When sandstorms come, we should not only recognize their symbols, but also take corresponding protective measures.