Baltimore sinkhole appeared in the city Wednesday, and it has been devastating. After a major storm made its way to the northeast of Baltimore, the long sinkhole followed, swallowing cars and causing the evacuation of many.

The Baltimore sinkhole opened alongside railroad tracks used by CSX on Wednesday afternoon in the first block of 26th Street.

The devastating effect of the Baltimore sinkhole prompted the evacuation of a block of rowhouses and a building inspector was reportedly also called in. CSX had to suspend rail traffic. Fortunately, according to the fire department, there were no injuries caused by the Baltimore sinkhole.

The city mayor's Twitter account tweeted residents to avoid the area affected by the Baltimore sinkhole.

As one tries to look at the bigger picture, the Baltimore sinkhole isn't the only sinkhole making the headlines. Just last month a large sinkhole appeared in between 2 houses in a neighbourhood called 'The Villages' in Florida. While nobody was hurt, just as the Baltimore sinkhole, it still is chilling to think anyone could have been swallowed by these sinkholes.

And it's not just the States affected by these sinkholes. While in America the latest has been the Baltimore sinkhole today, the UK is also reportedly suffering from a plague of sinkholes. In January, a 15ft hole has opened up on the M2, a 30ft crater swallowed a car in High Wycombe and in Hemel Hempstead, homes were evacuated after a sinkhole 35ft across opened up in a residential street, according to The Independent.

Many questions probably plague the minds of affected residents, especially in the most recent Baltimore sinkhole. But first, people need to understand what a sinkhole. Then the real question follows, why are they suddenly plaguing the earth?

What is a sinkhole?

A sinkhole, as with the Baltimore sinkhole, is in essence any hole in the ground created by erosion and the drainage of water. Although sinkholes are caused by natural processes, many sinkholes reported on the news nowadays, like the Baltimore sinkhole located in a residential area, are triggered by human activity.

What causes a sinkhole?

Sinkholes are known to occur in 'karst terrain' - a land where soluble bedrock (such as limestone or gypsum) can be dissolved by water. There are 2 types of sinkholes, cover-subsidence sinkholes and cover-collapse sinkholes, like the Baltimore sinkhole.

With cover-subsidence sinkholes, the bedrock becomes exposed and being worn down over time, the holes become ponds as water fills them in.

With a cover-collapse sinkhole like the Baltimore sinkhole, naturally occurring cracks and small voids under the bedrock are hollowed out by water erosion, with a cover of soil or sediment remaining over the top. As the hole expands over time, the cover collapses from the weight of, let's say, a house, a cemented road, a building - and reveals a wide gaping hole underneath.

Why the number of sinkholes now?

According to The Independent, most of the sinkholes we see now, such as the Baltimore sinkhole, are unknowingly created by human activity. These usually occur with human constructions where rain water has been concentrated on a particular patch of ground in the form of run-off from roofs and tarmac.

However, as one looks at the larger picture, the South East (where reports say most of the sinkholes have appeared), is a natural sinkhole country , as most of the bedrock is the soluble chalk.

How bad is the sinkhole situation in the world?

Though things are portrayed alarming in recent news, such as the Baltimore sinkhole, sinkholes are reportedly not as dangerous as they look. The Independent says the effects are localized and they can be safely dealt with. But this doesn't mean that sinkholes are completely safe and should be left to authorities.

One of the most devastating sinkholes happened in 2010 in Guatemala City when an approximately 65ft wide and 100ft deep area collapsed. This reportedly swallowed a three-storey factory and killed over 15 people. Factors which caused the sinkhole of are an influx of water from Tropical Storm Agatha and leakage from a local sewerage pipe.

Is there a way to prevent sinkholes?

There are warning signs that a sinkhole, like the Baltimore sinkhole, is about to happen. A brochure issued by the Southwest Florida Water Management District lists several sinkhole warning signs, which include slumping trees or fence posts, formation of small ponds in areas where water has not collected before, wilting of small, circular areas of vegetation; and structural cracks in walls.

Baltimore sinkhole has recently caused extensive damage to the city. For more information on sinkholes which can save your life, click here and here.