A lack of snow and mild weather posed huge challenges to Scotland's latest mountain snowsports season.
Andy Meldrum, of the Glencoe Mountain resort, said that while not the worst season in the centre's history, it was among its top three poorest.
Susan Smith, of Cairngorm Mountain, described the recent winter conditions as "unprecedented in recent times".
Glencoe, Nevis Range, Cairngorm, Glenshee and the Lecht used snow-making machines to keep lower slopes open.
Mr Meldrum, who is chairman of national body Ski Scotland, said 2018-19's winter had been challenging for Glencoe Mountain.
The resort was able to open on 1 December using its snow-making factory.
But Mr Meldrum said: "Natural snow didn't arrive in any volume until the beginning of February and even that only hung around for a couple of weeks before melting again.
"Snow then returned in mid March and we had a decent run of things closing for the season on 21 April."
He added: "It won't be the worst season but it will be up there in the top three poorest seasons with less than 10,000 skier days for the winter.
"The 2016-17 season was the worst season in history and we had just 4,600 skier days. This season we had 9,500."
A skier day means one person who skis or snowboards on one day. Many of the same people return to the slopes several times during the season.
Other seasons have had skier days running to six figures. Across all five mountain resorts, the 2012-13 season had 290,996 skier days and there were 235,303 in 2013-14 when Scottish centres had deeper snow than some Alpine resorts.
In 2010, skiing was still possible at Cairngorm until midsummer in June.
Ms Smith, interim chief executive of Cairngorm Mountain, near Aviemore, said snow was scarce in 2018-19.
She said: "All five Scottish ski resorts struggled this winter due to the mild weather and lack of snow.
"However, we were open for 31 snow sports days out of a probable 140 days.
Ms Smith added: "It's fair to say that last winter was unprecedented in recent times."
Like Glencoe, Cairngorm is planning to make improvements to its facilities over the summer. These include revamps of its uplift, such as chairlifts.
Trafford Wilson, chief executive of Snowsport Scotland, said the mountain resorts had worked hard to cope with challenges caused by warm temperatures and heavy rain.
He said: "However, despite challenging weather conditions, snow-making machines have allowed most ski resorts to open early and to operate beginner slopes and ski schools for the most of the season.
"Snowsports continues to be a popular sport in Scotland, with artificial slopes attracting a significant number of people - particularly young people - to the sport throughout the season and the mountain resorts playing an important role in allowing participants to progress their ski/board skills on snow."
'Poor followed by great'
Mr Wilson added: "Notwithstanding a challenging winter season, Snowsport Scotland's membership has increased this year and currently 23 Scottish athletes are represented on GB training squads."
Meanwhile, the thoughts of operators of the mountain centres are never far from the next winter conditions.
Ms Smith said: "The last two winter seasons have been poor in relative terms.
"We are hopeful that this winter will provide good snow cover and with the use of the Snow Factory we want to be open for skiing at the start of December 2019."
Mr Meldrum said: "As always we have our fingers crossed for 2019/20 being a great winter.
"Historically poor seasons have always been followed by great ones."