Falmouth Coastguard said it is currently coordinating the search for a 51-year-old man who was washed out to sea at Port William on the north Cornish Coast while scattering ashes.
Two other members of the group that he was with went into the sea in an attempt to rescue him but were unsuccessful.
Falmouth Coastguard scrambled a search and rescue helicopter from RAF Chivenor, two coastguard rescue teams from Boscastle and Port Isaac began a shoreline search and the Padstow RNLI Lifeboat was launched.
Falmouth Coastguard Watch Manager, Neil Oliver, said: "We have now been searching for four hours and sadly the man has not been found yet.
The helicopter and lifeboats have now completed their searches but the two coastguard rescue teams continue their search.
Conditions this evening have been unfavourable with gale force winds and rough seas."
A patient is being tested for the Ebola virus as a precautionary measure at the Royal Cornwall Hospital in Truro after being admitted last night.
The person - who was considered at risk of having contracted Ebola - has been placed in an isolation unit until the results of the test are known, the hospital said.
"We do not expect the results to be known for at least 24 hours and in the meantime the patient is being looked after in isolation", a spokesman said.
Royal Cornwall Hospitals NHS Trust "has taken the proper precautions and followed the guidelines" from Public Health England and NHS England, he added.
One of the country's most senior policemen has condemned the provision of mental health care for children in Britain as "unacceptable."
Paul Netherton, Assistant Chief Constable of Devon and Cornwall Police, took the highly unusual step of speaking out on social media after his officers were forced to keep a teenage girl in custody because, he said, there was no proper facility for her anywhere in the UK.
After his outburst, she has been found a bed tonight. But as ITV News reporter Duncan Golestani has more on what her plight has exposed - what some call - a worrying lack of care for the vulnerable
The chief executive of the mental health charity Mind has slammed the "terrible and shameful" situation which meant a girl with mental health issues was held by polic'
This is a terrible and shameful situation. Being in mental health crisis can be terrifying and life-threatening, and people need urgent care from mental health services.
Paul Farmer said a police cell was a "completely inappropriate place to put someone who is so unwell", adding: "This whole episode shows how thinly spread NHS mental health services are."
Thousands of people with mental health issues are being taken into police custody every year because of a lack of mental health care provision, a leading charity has warned.
Mark Winstanley, chief executive of Rethink Mental Illness, said while the teenage girl being held for two days was “troubling”, it was far from an isolated incident.
Each year thousands of people with serious mental health problems are being held in police cells, including many children and teenagers, because the right services either don't exist in their community or are completely overstretched.
Being held in a police cell can be extremely distressing, and should only ever happen as an absolute last resort.
But many people are being turned away from 'places of safety', because of staff shortages or lack of spaces. In some parts of the country, there are no health-based places of safety full-stop.
The girl has now been found a place locally, NHS bosses have confirmed.
The police chief who raised awareness of a major shortage in NHS mental health care beds has welcomed news that a teenage girl is to leave police custody after a place was finally found.
Just heard that a place of care has been found for our 16yr old. Good result.
Mental health experts have criticised “unacceptable” cutbacks to services in the UK which led to a teenage girl being forced to stay in police custody as the NHS could not accommodate her for two days.
Chief executive of the Royal College of Nursing, Dr Peter Carter, said over the past four years more than 3,300 mental health nursing posts had been lost along with 1,500 available beds, despite a 30 per cent rise in the number of patients needing care.
It's appalling that any patient should be taken into police custody due to a lack of mental health beds - it's particularly unacceptable that it should happen to a 16-year-old.
These cutbacks are having a devastating impact on those who desperately need care and support. It's a terrible indictment of this country's inadequate mental health provision.
A teenage girl with mental health issues who was being held in police custody due to there being "no beds available in the UK" will be moved this evening, NHS England has said.
A spokesman for NHS said the girl she would be moved to a "place appropriate for her care".
The mother of a teenage girl with mental health issues has taken a “big box of chocolates” in to police officers keeping her daughter in custody due to a shortage of NHS beds.
The 16-year-old was detained by Devon and Cornwall Police on Thursday night and sectioned yesterday – but with officers being told there was nowhere in the UK to transfer her to, they have kept her in the custody suite.
Asst Ch Con Paul Netherton said the girl’s mother was “grateful” that the force was taking care of her. They have even taken her a McDonald’s meal, he added.
NHS England has said it is working with police to establish the exact needs of a teenage girl currently being held in custody, with the aim of arranging suitable care.
A spokesman added the number of people with mental health issues ending up in police custody was down by a quarter overall.
We are immediately asking the police for proper information about the needs of this 16-year-old girl so the NHS locally can urgently arrange appropriate care for her wherever it is available.
More broadly, it is worth noting that mental health crisis services have been expanding so that the number of people ending up in police cells is in fact down by a quarter - but clearly there is more to do.