Flights have been cancelled from Catania Airport with a cloud of ash rising 4,500m over Mount Etna.

The Volcano Observatory Notice for Aviation states that the ash is moving in a southerly direction.

It reads: "Strong strombolian activity is observed at summit craters, strong ash emission ongoing. Volcanic height: estimated volcanic height is about 4,500m at the top."

A yellow alert is in place by Italian authorities following the eruption of Mount Etna.

The Civil Protection Department states: "Alert levels describe the state of volcano activity, i.e. whether the volcano is in a state of equilibrium or disequilibrium. They are identified based on a combination of monitoring parameters and data from any ongoing events.

"They are represented by four colors - green, yellow, orange and red - which are indicative of the possible evolution of the state of volcano activity towards event scenarios "of national importance", which require to be faced with extraordinary means and powers, through the coordinated intervention of a plurality of subjects."

A passenger says that he was waiting for four hours at Palermo Airport after his flight to Catania was diverted - and without buses he has had to pay 600 euros for a taxi.

He wrote on Facebook: "Departure with over an hour delay, flight diverted to Palermo and, once landed, another hour waiting in the plane without any information. At the airport, total chaos: no order in flight management, no indication of buses to reach Catania, no assistance and not even a bottle of water after hours of waiting.

"We’ve been standing for about four hours waiting for buses that never came. In the end we were forced to pay for a taxi, spending around 600€, not knowing if we will ever get a refund.

"Etna’s activity is certainly not something new, it’s a situation that happens regularly. For this reason you would expect an efficient organizational plan and an appropriate assistance for passengers. On the contrary, the impression was of a total improvisation.

"At this point it would have been much better to cancel the flight, instead of passengers wasting hours to land at an airport two and a half hours away from their final destination, without any support."

A statement on Facebook from Palermo Airport reads: "Since July 5, because of the eruption of Etna, Palermo Airport has done its best, facing the commercial traffic on July 5, with 114 incoming flights and 112 departures, and on July 6 (115 and 117) - the arrival of 33 additional flights (situation updated on July 6 at 7.30am) diverted from #catania for the #volcano emergency.

"At this moment, we are aware that there may be some inconveniences, we are working at a great pace to ensure the best travel experience for passengers transitioning from our stopover and to assist. Every passenger on Catania flights will be taken on buses arranged by the airlines to Fontanarossa Airport."

A passenger has told how her diverted flight landed at Palermo at 10pm and she is still waiting this morning for a bus to Catania., calling it a "deplorable situation".

She says that due to the number of eruptions from Mount Etna, the airports should be better prepared.

"We are still waiting for buses to take us to Catania. At Palermo airport, there was very little support - a few police officers facing hundreds of angry people who tried to get on the few buses that arrived." she told Catania Today.

"There are disabled people, babies, and the elderly camped out in the airport."

Mount Etna is Europe's largest, tallest, and most active volcano.

Located on the eastern coast of Sicily, Italy, it rises approximately 3,400 metres above sea level, dominating the landscape between the major cities of Catania and Messina.

It is an active stratovolcano, continually changing shape and height with every summit eruption. Normally it produces mildly explosive Strombolian eruptions and slow-moving effusive lava flows.

Etna erupts multiple times a year, averaging around 13 to 17 distinct eruptive events annually during its highly active phases. Because the volcano is in a state of near-continuous persistent activity, it can experience several eruptive bursts within a single month.

A red alert remains in place for aviation by Mount Etna.

The Volcano Observatory Notice for Aviation has not updated the warning which was issued at 3.12am saying there was "strong Strombolian activity from the summit craters and ongoing heavy ash emission".

According to indications, the ash cloud is directed south and southeast today, resulting in Catania airport being affected.

A latest statement from Catania Airport reads: "Following the volcanic activity that occurred during the night between Sunday, July 5th and Monday, July 6th, all incoming flight operations remain suspended, and departures are stopped, currently until 2:00 PM.

"Passengers are kindly requested not to travel to the airport unless they have first checked the status of their flight with their airline."

Catania airport’s website shows a long list of flights which are either diverted, cancelled or currently delayed until this evening.

Passengers are being asked to not to travel to the airport this morning.

Passengers are being asked to check the status of their flights with their airlines before traveling to Catania Airport today.

The airport currently remains closed until midday for both incoming and outgoing flights due to Mount Etna erupting.

Some flight are being diverted to Palermo airport on the north west of Sicily.

Flights into Catania Airport are still being affected by the Mt Etna eruption this morning.

A flight due to land at the airport from London Gatwick at 7.10am was cancelled and another from Luton due to land at 8am will now touchdown at 2pm.

Passengers area advised to contact their airline before travelling to Sicily.

Mount Etna is located in what is known aqsthe continental collision between the Eurasian and African plates.

Extensional faults occur in this area, which has allowed magma to rise from the Earth's mantle.

Information by the Italian Civil Protection Department reads: "The lava flows of Etna, due to their viscosity and consequent low sliding speed, are not such as to constitute a danger to the safety of people.

"In the case in which the leakage occurs from the mouths placed at high altitude, the flows would rarely reach the towns .

"Only in the case of eruptions of long duration, such an eventuality can occur."

Etna's eruptive vents are located at the summit of the volcano and the Bocca Nuova, Voragine Cratere of north-east and Cratere of south-east, according to the Italian Civil Protection Department.

Each of them has a diameter of about 200 meters.

Etna is the largest volcano in Europe.

The volcano is 3350m above sea level and 35km in diameter at the base.

Lava was seen along Mount Etna's eastern flank after on July one after an eruptive fissure opened at eastern base of Voragine summit crater.

A statement from the management company of Catania Airport said: "Following today's volcanic activity and due to shifting winds, the area corresponding to the south-west air cloud (sector C1) has been closed until 5am tomorrow morning, July 6."

As a result, all evening and overnight flights due to arrive at the airport have been suspended. However, departures for aircraft already on the ground are still operating.

"Passengers are asked to check the status of their flights with their airlines before heading to the airport. Updates will follow in the coming hours," the statement added.

You can watch the livestream here.

Mount Etna has put on a fiery display this evening, with a livestream on afarTV capturing the volcano's Strombolians eruptions in all their glory.

These eruptions consist of short, rhythmic bursts of gas that eject glowing pieces of magma from a volcanic vent. The fragments - which range from large volcanic bombs and lava clots to fine lapilli and ash - are typically thrown tens to hundreds of metres into the air.

Due to ongoing volcanic ash in the atmosphere, flight restrictions remain in place at Catania Airport, according to Sicilian broadcaster Radio Una Voce Vicina.

As we previously reported, sector B2 of the airspace - the area on the southern side of Mount Etna affected by the volcanic ash cloud - has been closed. Catania Airport said the closure will remain in place until 7pm local time (6pm BST). It is not yet clear whether it has been lifted.

Restrictions on incoming flights will remain in place until 9pm local time (8pm BST), with arrivals capped at five per hour. Departures from the airport are not restricted.

Passengers are being advised to check their flight status before travelling.

Palermo Airport in Sicily is experiencing unusually high passenger volumes following flight disruptions caused by Mount Etna’s increased Strombolian activity, according to local reports.

Palermo Today reported that 23 flights were diverted from Catania Airport to Palermo Airport.

Mount Etna is producing small explosions of ash and volcanic fragments - a type of activity known as Strombolian eruptions.

Named after the nearby island volcano of Stromboli, this type of eruption involves short, regular bursts of gas that eject glowing pieces of magma from a volcanic vent. These fragments can include volcanic bombs, lava clots, lapilli and ash, and are typically thrown tens to hundreds of metres into the air.

• There is increased volcanic activity at Mount Etna, which stands around 11,050ft above sea level on the east coast of Sicily.
• Europe's most active volcano is releasing a large plume of ash from a vent on the upper eastern flank of the Voragine summit crater.
• The ash cloud rose about a mile above the summit before drifting south with the wind.
• A lava flow that had been active since June 26 stopped on Saturday (July 4), but the volcano is still producing small, frequent explosions known as Strombolian eruptions.
• Due to the volcanic ash, aviation authorities have kept the Volcano Observatory Notice for Aviation at 'red', its highest alert level.
• The ash cloud has led to temporary airspace restrictions, causing flights arriving at Catania Airport to be suspended.

Etna stands around 11,050ft above sea level and is about 22 miles in diameter, although volcanic activity has altered the mountain's height over time.

Occasionally, Catania Airport, the largest airport in eastern Sicily, has to close for hours or even days when volcanic ash makes flying in the area dangerous.

With Etna’s lava flows largely contained to its uninhabited slopes, life continues in towns and villages elsewhere on the mountain. The volcano also supports fertile farmland and attracts tourists.

The volcano has inspired ancient Greek legends. An eruption in 396 BC is said to have kept the Carthaginian army at bay.

In 1669, during what is considered the volcano's worst known eruption, lava buried parts of Catania, about 15 miles away, and devastated dozens of villages. Another eruption, in 1928, cut off a rail route circling the mountain’s base.

In a post on Instagram six hours ago, Catania Airport said: "Due to this morning's volcanic activity on Sunday, 5 July, Sector B2 has been closed, and arrivals have been limited to five flights per hour until 9pm (local time).

"Passengers are advised to check the status of their flight with their airline before travelling to the airport. Further updates will be provided as they become available."

We are awaiting further updates on how long disruption at the airport will continue.

Incadescent lava was observed just days ago on Mount Etna before its eruption, on July 1.

The National Institute of Geophysics and Volcanology, through the Etna Observatory, has raised the aviation alert from orange to red following the activity at the summit today.

According to La Sicilia, intense volcanic ash emissions have prompted a warning for aviation that the phenomenon "is in full swing".

A red alert is given when an ash cloud poses a potential risk to aircraft.

Experts continue to monitor the situation through visual and thermal cameras installed on the volcano.

Lava was spotted burning bright into the night sky from Catania just days ago on July 1.

An orange glow from Mount Etna could be spotted on its eastern flank, following reports of an eruptive fissure at its eastern base.