When it's snowing or has just snowed, freshly packed snow makes a crunching sound when you step on it, showing that it's light and fluffy. Walking on this type of snow is generally not too difficult.
When temperatures rise above 0°C or sunlight melts the snow, the road surface becomes slushy. It's not particularly slippery, but water can easily seep into your shoes, which can make walking uncomfortable.
When melted snow refreezes, the road surface becomes extremely icy and slippery, greatly increasing the risk of falling. Sometimes a layer of ice hides under fresh snow, so extra caution is needed.
Even crosswalks that look safe can have frozen asphalt or icy painted lines. The difference between appearance and reality often causes people to let their guard down, making these spots particularly dangerous.
Some intersections in urban areas have boxes filled with anti-slip sand. The sand provides better traction for your shoes and makes walking easier than on untreated icy roads.