The return of warm conditions has many Calgarians basking, and sneezing, in the sunshine and a local physician says most people are unaware of what’s causing their red eyes and runny noses.

“It’s called snow mould but it grows below the snow,” explained Dr. Sakina Raj. “When it gets warmer and it melts, that’s the time you see two types - white, like grey, mould and pink mould. They both do the same thing. One makes less spores than the other but both will give the same symptoms.”

Raj says an estimated 60 to 70 per cent of the population will react to snow mould and the symptoms are similar to those of a cold. Sufferers will likely experience a runny nose, swelling in the eyes and throat and a possible rash.

“People don’t know about snow mould and they’re not prepared.”

She says mild symptoms can be controlled through preventative measures including reducing exposure to the mould and nasal rinses while more severe symptoms may require antihistamines or nasal sprays.

Raj recommends breaking ice around your home to hasten the melting process.

“Wind and heat kill this mould,” said Raj. “When it goes above 20 degrees centigrade, they’ll be gone, or if it’s very windy then the spores will be gone.”

To further reduce exposure, Raj recommends not raking your lawn in the spring unless you’re wearing an allergy mask and to avoid leaving doors and windows open to prevent spores from entering your home.

While snow mould is a foreign concept to many Calgarians, Darryl McCoy knows the symptoms all too well.

"My allergies can actually disable me for one or two days depending on how bad they are and how bad the conditions are." said McCoy. “Last year was really bad. I actually took three days off because of my allergies.”

The Calgarian, who is also allergic to dust and cat hair, says his physical suffering is a somewhat unwelcome sign of spring's arrival.

“I’ve learned to live with it. It’s usually only a couple of weeks and I’ll take the nice weather over the crappy weather any day,” laughs McCoy. "Especially this year."

Dr. Raj says snow mould is not unique to Calgary but she has observed a trend in the way it affects newcomers. Raj’s patients include a number of immigrants and refugees and she says the patients do not experience snow mould allergy symptoms during their first spring in Canada but the symptoms appear in year two.

With files from CTV’s Brad MacLeod