Dlouhé stráně, Mountain summit in Loučná nad Desnou, Czech Republic.

Dlouhé stráně is the highest summit of the Desenská hornatina, a district of the Hrubý Jeseník, at 1354 m, 4 km southeast of Kouty nad Desnou. Its top was cut flat in 1978 to hold the upper reservoir of the Dlouhé Stráně pumped-storage plant, an irregular oval about 710 m long and 240 m wide, with rock blocks and alpine meadow around it.

Until 1978 the summit had a rounded dome shape, reaching 1350.3 m. That year the Czechoslovak government decided to build the upper reservoir of the Dlouhé Stráně pumped-storage plant; the top was cut off and the excavated rock used to widen the reservoir's base, giving the summit its flat, trapezoid profile.

The summit's shape changed after 1978, when the Czechoslovak government approved the upper reservoir of the Dlouhé stráně pumped-storage plant: the dome was cut and the excavated rock used to widen the reservoir's base. The reservoir now forms an irregular oval about 710 m long and 240 m wide.

The summit is reached by a red-marked trail from Kouty nad Desnou, or by a small road from the lower reservoir; the cable car to Medvědí hora shortens the walk to under 3 km. The summit viewpoint sits by the southern edge of the reservoir, with rock blocks and a signposted height of 1353 m.

The summit's original dome shape was cut down after 1978 to build the upper reservoir of the Dlouhé stráně pumped-storage plant; the excavated rock was used to widen the reservoir's base. The reservoir is an irregular oval about 710 m long and 240 m wide, and the plant's two reversible Francis turbines give it an installed output of 2 × 325 MW, the highest of any hydro plant in Czechia.