Why has Henan become the center of heavy rain again?

Why has Henan become the center of heavy rain again?

Why has Henan become the center of heavy rain again? From August 21st to 24th, there will be a heavy rainfall weather process from west to east in my country, affecting 9 provinces In Sichuan and Henan, the rainfall may be the strongest. A very typical feature of this rainfall process is that not only is the rain heavy, but the wind is also extremely strong. Why has Henan become the center of heavy rainstorms again 1

Experts remind us to be wary of the superimposed effects of strong winds and heavy rains

According to the forecast of the Central Meteorological Observatory, from August 21st to 24th, there will be a strong storm in my country from west to east. Rainfall weather process. Among them, Henan, which just experienced the "7·20" heavy rainstorm, will experience heavy rainfall again after a month.

How does the intensity of this heavy rainfall compare with the "7·20" heavy rain? Is the risk of disaster high? A reporter from China Meteorological News invited Zhang Tao, chief forecaster of the Central Meteorological Observatory, to give an authoritative interpretation.

The strongest rainfall affects 9 provinces and cities in Sichuan and Henan.

Zhang Tao said that this heavy rainfall has the characteristics of wide impact, strong local rainfall, and fast system movement. At the same time, in There are strong winds in the Huanghuai area. Since this process moves relatively fast, the cumulative rainfall will not be particularly extreme, but the short-term rainfall intensity is relatively large, which requires attention. This rainfall overlaps the previously affected areas in Henan and has a very large impact. Reservoirs, lakes, and rivers need to be prepared. .

Zhang Tao explained that from the perspective of system configuration, this heavy rainfall process is a very typical monsoon rainfall. The subtropical high pressure extends westward, allowing warm and humid water from the Indian Ocean, South China Sea, and Western Pacific Ocean. The air flow smoothly moves northward along the western edge of the subtropical high pressure, confronting the cold air from the north, causing widespread rainfall.

Heavy rainfall affects a wide range of areas. Nine provinces (cities) including Sichuan, Chongqing, Shaanxi, Shanxi, Henan, Hubei, Anhui, Shandong, and Jiangsu are all in heavy rainfall areas. Generally speaking, moderate to heavy rains are the main force, but in several relatively concentrated places, there will be Heavy rain. Among them, the Sichuan Basin and Henan have the strongest rainfall, with local rainfall reaching 250 to 400 millimeters, which is already a heavy rainfall level.

Henan needs to be wary of superimposed impacts causing disasters

In this process, Henan is also the center of heavy rains. One month later, people can't help but think of the "7·20" heavy rain in Henan last month. What are the similarities and differences in the intensity and causes of the two processes?

Zhang Tao said that the process of heavy rain in Henan this time was different from that of "7·20". This rainfall process is mobile and will not reproduce the "hesitation" of previous rainfall, so the cumulative rainfall will not be particularly extreme. Furthermore, this process is a heavy rain caused by the combination of airflow and water vapor guided by the western side of the subtropical high, which is a typical rainstorm configuration during the flood season. In contrast, during the "7·20" process, the typhoon and the subtropical high were at sea and far away. It is an indirect effect, coupled with the "chemical reaction" of water vapor and topography, which is not only unique this summer but also rare in history, and ultimately led to the rare record-breaking heavy rain.

However, Zhang Tao reminded that although the cumulative rainfall this time will not be particularly extreme, it may still have a very large and adverse impact on Henan. Because the impact of the extreme rainstorm in Henan a month ago has not yet completely passed, and the area of ??this rainfall overlaps with the areas affected by previous heavy rains, it is particularly recommended that the local area prepare for flood control, drainage and emergency response in advance.

Henan, Shandong and other places still need to be prepared for strong winds

Zhang Tao said that a very typical feature of this rainfall process is that it is not only heavy rain, but also extremely windy. powerful. As the summer and autumn seasons change, the cold air in the north gradually becomes active. During the collision with the warm and humid air flow from the south, three cyclones are "kneaded" and fall on the line from southwest to northeast. They are located in the northeast, the eastern part of the northwest to Henan and Shandong. , and the Sichuan Basin. These three areas are also the areas where rainfall is concentrated this time.

Especially the cyclones from the eastern part of the northwest region to Henan and Shandong bring strong winds with them as they move eastward along Henan and Shandong. The strong winds increase the rainfall and are more destructive.

From a prevention perspective, the areas along the route where this cyclone passes can treat this process as a "tropical cyclone on land" and take precautions with high standards. According to the forecast, from the 22nd to the 24th, there will be rotating winds of magnitude 4 to 6 and gusts of magnitude 7 to 9 in central and eastern Henan, most of Shandong and the Yellow Sea. Local gusts can reach magnitude 8 to 11.

Therefore, Henan, Shandong and other places need to strengthen outdoor billboards and temporary structures to reduce or avoid high-altitude operations; the Yellow Sea needs to prevent the adverse effects of strong winds on passing ships and maritime operations.

The process is still uncertain and we need to pay attention to strong convective weather

Zhang Tao reminded that the three cyclones "kneaded" out of the intersection of cold and warm air in this process , the approximate location and intensity of the three rainfall centers can currently be predicted. But what we also need to pay attention to is the much smaller-scale severe convective weather processes that may be hidden under the three rainfall centers. These strong convective processes, like "small bubbles after water boils", are small- and medium-scale systems that truly determine the extremeness of single-point rainfall.

According to the laws of nature, the smaller the scale, the greater the uncertainty and the lower the predictability. Therefore, all localities need to dynamically pay attention to the rolling updates of short-term nowcast warnings from local meteorological departments. information. Why Henan has become the center of heavy rain again 2

From August 21st to 24th, there will be a heavy rainfall weather process from west to east in my country, affecting 9 provinces and cities, with Sichuan and Henan experiencing the strongest rainfall.

It has just been one month since the "720" heavy rain disaster, and Zhengzhou, which is still rebuilding after the disaster, will encounter another heavy rain or heavy rain.

On the evening of August 18, the Henan Provincial Flood Control and Drought Relief Headquarters Office issued an emergency notice, requiring relevant units in various places to effectively prepare for and respond to the upcoming three rounds of heavy rainfall.

According to the forecast of the Henan Provincial Meteorological Department, on August 22, there will be heavy rains or heavy rains in some counties and cities north of the Yellow River and Sanmenxia, ??Luoyang, Zhengzhou, Kaifeng, Xuchang, Shangqiu and other places. Local heavy rains will occur in most places. The regional precipitation is 70 to 100 mm, with 150 to 180 mm in some counties and cities, and up to 200 to 300 mm in some places. The maximum hourly rainfall intensity is 70 to 90 mm.

On the 20th, with the sun shining brightly, The Paper visited urban tunnels and subway entrances in Zhengzhou, interviewed communities, hospitals, etc., and found that flood prevention measures or preparations had been taken. Although the forecast shows that the heavy rain this time is not as serious as "720", many citizens still have lingering fears. Many citizens said they had purchased safety hammers before, and some even purchased kayaks. On the evening of August 18, some citizens drove their cars onto the viaduct. Some Henan media said, "I heard that a heavy rain was coming, and the people in Zhengzhou reacted too hard!"

Water retaining boards have been installed at the subway entrances, and roadblocks have been prepared at the tunnel entrances

8 At noon on March 20, the weather in Zhengzhou was sunny, with the highest temperature that day being 32 degrees Celsius.

The Paper randomly checked multiple stations of Zhengzhou Metro Line 3 and Line 5 and saw that the entrances and exits of the stations were all closed with iron gates. Behind the hollow iron gate, a waterproof aluminum baffle 50 to 60 centimeters high is installed, and flood control sandbags are piled behind the baffle.

Waterproof baffles installed at subway entrances. The pictures in this article are all pictures by The Paper reporter Duan Yanchao

At 14:00 on the 20th, staff at the People’s Park Station of Line 3 He told The Paper that because the site has three underground floors, it was severely damaged in the past. It has been under construction recently, so the entrances and exits are open. After receiving the rainfall warning on August 18, the subway took measures to install waterproof aluminum baffles and stack sandbags at the entrances and exits of all stations. He introduced that his location on Line 3 has conducted flood prevention drills in the past two days. Although the subway has not resumed operations, the drill still includes comforting and evacuating passengers, preventing water intrusion at all entrances and exits, and protecting facilities. Moreover, at 23:00 on the 20th, staff at all stations on Line 3 will collectively conduct flood prevention emergency drills.

The staff member said that she did not know the situation of other subway lines, but they should be similar because the group has flood prevention requirements.

According to the official website of Zhengzhou Metro Group Co., Ltd. on August 19, the "720" heavy rainstorm disaster caused the entire Zhengzhou Metro network to be suspended. After all-out emergency repairs, Zhengzhou Metro Lines 4, 5, and 2 The second phase of Line 1 has realized no-load operation, and Line 1, Line 2, Phase 1 and Suburban Railway Phase 1, which were suspended from no-load operation due to epidemic prevention and control, have resumed no-load operation. Zhengzhou Metro is fully cooperating with the safety assessment and striving to implement passenger operations as soon as possible.

In urban Zhengzhou, reporters from The Paper randomly observed that emergency roadblocks were placed at every tunnel entrance and exit they passed, most of which were retractable roadblocks 50 to 60 centimeters high. The Jingguang Road Tunnel (including the South Road Tunnel, the Middle Road Tunnel, and the North Road Tunnel), which caused 6 deaths in the "720" heavy rain disaster and attracted much attention, is even more prepared. The Paper reporter saw that each tunnel entrance and exit was not only equipped with yellow iron roadblocks more than one meter high, but also equipped with road cones, red plastic water shields, and warning lights.

Roadblocks and waterproof baffles are prepared at the entrance of the Jingguang North Road Tunnel

In this regard, the staff of the Zhengzhou Urban Tunnel Comprehensive Management and Maintenance Center introduced, The center worked with the traffic police department to install traffic-breaking facilities at the entrances and exits of the eight tunnels under its management (including the Jingguang Road Tunnel). The traffic interruption facilities installed this time are mainly roadblocks to cooperate with the traffic police for traffic control, and special personnel will be arranged to be on duty when it rains. Once the tunnel is seriously flooded, the road will be closed in time.

The Paper also noticed that where there are construction pits on the road, warning signs are erected, and warning lights and road cones are erected in the direction of oncoming traffic.

Warning signs set up on the road

Hospitals, schools and communities have taken measures, and some citizens even bought kayaks

The Paper Driving along Haihang Road (the section from Zijingshan Road to Jingguang Road), I saw flood control sandbags piled at the entrances of many businesses on both sides of the road. A staff member at a gas station near the intersection of Haihang Road and Zijingshan told The Paper that the gas station is located on a relatively high ground, and during the "720" heavy rainstorm, water almost flooded into the business hall. In the face of the upcoming heavy rain, Zhengzhou Company has issued a notice. In addition to preparing flood prevention materials, the gas station also conducted a flood prevention drill on the morning of the 20th.

In Jingguang Road Community, Erqi District, at the north entrance of Jingguang North Road Tunnel, the west gate (main entrance) has been locked, and one-meter-high flood control sandbags are piled at the door. The guard told The Paper that because the terrain of the community is high in the west and low in the east, during the "720" heavy rainstorm, all the water that poured into the school flowed out from the east gate, so the water in the school was not deep, only ten or twenty centimeters. This time, I heard that the education department issued flood prevention requirements. The school has already prepared flood prevention materials. When it rains, school leaders will be on duty and have plans in place.

A primary school with sandbags piled up at the entrance

During the "720" heavy rainstorm, many hospitals in Zhengzhou City were severely damaged. Currently, Zhengzhou is in a critical period of fighting the epidemic. The relevant person in charge of the Zhengzhou First People's Hospital Port District Hospital, which is the designated hospital for the treatment of COVID-19, said that the hospital is located in a high location and there was basically no water on the ground during the previous heavy rainstorms. However, the hospital has made adequate flood prevention preparations and plans for the upcoming heavy rain. According to him, the hospital has two CT trucks outside and are fully prepared for rain protection. More importantly, as a designated hospital, it is necessary to strictly prevent the spread of pollution, etc., and has focused on strengthening flood prevention preparations at medical waste storage and processing points to speed up turnover and removal. In addition, the protection of sewage treatment facilities has been strengthened to prevent backflow and discharge.

Mr. Zhang, a citizen, lives in a community in Guancheng District. During the "720" heavy rainstorm, there was no water accumulation in the community. Although the water on the road outside the community was 30 centimeters higher than the entrance of the underground garage of the community, fortunately, the property management took measures to Timely measures were taken to temporarily block the entrance of the garage with wooden boards, pile up sandbags behind it, and put people on duty 24 hours a day, so no vehicles in the community were affected. In the face of this heavy rain, the community property management has reinforced professional water baffles on both sides of the garage entrance. Once a heavy rain comes, when necessary, the closing and locking operation only takes 10 seconds, and then the sandbags next to it are placed behind the water baffles and sealed. Just stay in the gap.

“In view of the performance of the flood-damaged property last time, I paid the property fee immediately when I needed to pay it recently.” Mr. Zhang said with a smile.

Many Zhengzhou car owners interviewed said that after the "720" heavy rainstorm, they all bought safety hammers and some even bought life jackets.

Mr. Cao even bought an inflatable kayak and three sets of life jackets. In the resettlement housing community where Mr. Cao lives, during the "720" heavy rainstorm, the two-story underground garage was filled, many vehicles were submerged, and the water in the community was up to waist level. Until now, the community still has temporary electricity, the underground garage is still under repair, and the owners’ vehicles are parked outside. This time, Mr. Cao was more worried. He called the property management company specifically and received a reply saying that preparations for flood prevention were in place, but he always felt uneasy. He repeatedly asked where the sandbags were, and the property manager said they were in the warehouse. He urged them to be piled at the door as soon as possible.

When The Paper passed by an underpass of the Jingguang Road Viaduct, he saw seven or eight cars parked in the emergency lane of the underpass. There were BMWs and Porsches, but no one was in the car. According to Henan media reports, when seeing the heavy rain coming again, some citizens bluntly said that they were "flustered". The underground garages of some communities were already empty, and the owners parked their cars on higher ground. Parking vehicles were already parked on the side road of Longmen Bridge of Longzi Lake. Full of private cars. Some insurance companies have reminded car owners to pay attention to the warning. Some communities prepared sandbags and water pumps early and conducted flood prevention drills in advance. In communities with old and dilapidated buildings, residents and businesses have been notified in advance to evacuate to safe areas.

Private cars parked at the entrance of the viaduct.

However, some citizens expressed calmness, "As long as we have awareness and measures to prevent it, there is nothing to fear from heavy rains."